diff --git a/package.json b/package.json
index b2add06..8a7f3f9 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,7 @@
     "mkdirp": "^0.5.0",
     "rimraf": "^2.5.3",
     "rsvp": "^3.0.18",
-    "username": "^1.0.1"
+    "username": "^2.3.0"
   },
   "devDependencies": {
     "chai": "^3.2.0",
diff --git a/yarn.lock b/yarn.lock
index a7b59e0..c4dd27e 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -24,10 +24,6 @@ argparse@^1.0.7:
   dependencies:
     sprintf-js "~1.0.2"
 
-array-find-index@^1.0.1:
-  version "1.0.2"
-  resolved "https://registry.npmjs.org/array-find-index/-/array-find-index-1.0.2.tgz#df010aa1287e164bbda6f9723b0a96a1ec4187a1"
-
 assertion-error@^1.0.1:
   version "1.0.2"
   resolved "https://registry.npmjs.org/assertion-error/-/assertion-error-1.0.2.tgz#13ca515d86206da0bac66e834dd397d87581094c"
@@ -55,25 +51,10 @@ browser-stdout@1.3.0:
   version "1.3.0"
   resolved "https://registry.npmjs.org/browser-stdout/-/browser-stdout-1.3.0.tgz#f351d32969d32fa5d7a5567154263d928ae3bd1f"
 
-builtin-modules@^1.0.0:
-  version "1.1.1"
-  resolved "https://registry.npmjs.org/builtin-modules/-/builtin-modules-1.1.1.tgz#270f076c5a72c02f5b65a47df94c5fe3a278892f"
-
-camelcase-keys@^2.0.0:
-  version "2.1.0"
-  resolved "https://registry.npmjs.org/camelcase-keys/-/camelcase-keys-2.1.0.tgz#308beeaffdf28119051efa1d932213c91b8f92e7"
-  dependencies:
-    camelcase "^2.0.0"
-    map-obj "^1.0.0"
-
 camelcase@^1.0.2:
   version "1.2.1"
   resolved "https://registry.npmjs.org/camelcase/-/camelcase-1.2.1.tgz#9bb5304d2e0b56698b2c758b08a3eaa9daa58a39"
 
-camelcase@^2.0.0:
-  version "2.1.1"
-  resolved "https://registry.npmjs.org/camelcase/-/camelcase-2.1.1.tgz#7c1d16d679a1bbe59ca02cacecfb011e201f5a1f"
-
 center-align@^0.1.1:
   version "0.1.3"
   resolved "https://registry.npmjs.org/center-align/-/center-align-0.1.3.tgz#aa0d32629b6ee972200411cbd4461c907bc2b7ad"
@@ -107,11 +88,12 @@ concat-map@0.0.1:
   version "0.0.1"
   resolved "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz#d8a96bd77fd68df7793a73036a3ba0d5405d477b"
 
-currently-unhandled@^0.4.1:
-  version "0.4.1"
-  resolved "https://registry.npmjs.org/currently-unhandled/-/currently-unhandled-0.4.1.tgz#988df33feab191ef799a61369dd76c17adf957ea"
+cross-spawn-async@^2.1.1:
+  version "2.2.5"
+  resolved "https://registry.npmjs.org/cross-spawn-async/-/cross-spawn-async-2.2.5.tgz#845ff0c0834a3ded9d160daca6d390906bb288cc"
   dependencies:
-    array-find-index "^1.0.1"
+    lru-cache "^4.0.0"
+    which "^1.2.8"
 
 debug@2.2.0:
   version "2.2.0"
@@ -125,7 +107,7 @@ debug@^2.1.3:
   dependencies:
     ms "0.7.2"
 
-decamelize@^1.0.0, decamelize@^1.1.2:
+decamelize@^1.0.0:
   version "1.2.0"
   resolved "https://registry.npmjs.org/decamelize/-/decamelize-1.2.0.tgz#f6534d15148269b20352e7bee26f501f9a191290"
 
@@ -147,12 +129,6 @@ editions@^1.1.1:
   version "1.3.3"
   resolved "https://registry.npmjs.org/editions/-/editions-1.3.3.tgz#0907101bdda20fac3cbe334c27cbd0688dc99a5b"
 
-error-ex@^1.2.0:
-  version "1.3.1"
-  resolved "https://registry.npmjs.org/error-ex/-/error-ex-1.3.1.tgz#f855a86ce61adc4e8621c3cda21e7a7612c3a8dc"
-  dependencies:
-    is-arrayish "^0.2.1"
-
 escape-string-regexp@1.0.5:
   version "1.0.5"
   resolved "https://registry.npmjs.org/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz#1b61c0562190a8dff6ae3bb2cf0200ca130b86d4"
@@ -184,25 +160,25 @@ esutils@^2.0.2:
   version "2.0.2"
   resolved "https://registry.npmjs.org/esutils/-/esutils-2.0.2.tgz#0abf4f1caa5bcb1f7a9d8acc6dea4faaa04bac9b"
 
+execa@^0.4.0:
+  version "0.4.0"
+  resolved "https://registry.npmjs.org/execa/-/execa-0.4.0.tgz#4eb6467a36a095fabb2970ff9d5e3fb7bce6ebc3"
+  dependencies:
+    cross-spawn-async "^2.1.1"
+    is-stream "^1.1.0"
+    npm-run-path "^1.0.0"
+    object-assign "^4.0.1"
+    path-key "^1.0.0"
+    strip-eof "^1.0.0"
+
 fast-levenshtein@~2.0.4:
   version "2.0.6"
   resolved "https://registry.npmjs.org/fast-levenshtein/-/fast-levenshtein-2.0.6.tgz#3d8a5c66883a16a30ca8643e851f19baa7797917"
 
-find-up@^1.0.0:
-  version "1.1.2"
-  resolved "https://registry.npmjs.org/find-up/-/find-up-1.1.2.tgz#6b2e9822b1a2ce0a60ab64d610eccad53cb24d0f"
-  dependencies:
-    path-exists "^2.0.0"
-    pinkie-promise "^2.0.0"
-
 fs.realpath@^1.0.0:
   version "1.0.0"
   resolved "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz#1504ad2523158caa40db4a2787cb01411994ea4f"
 
-get-stdin@^4.0.1:
-  version "4.0.1"
-  resolved "https://registry.npmjs.org/get-stdin/-/get-stdin-4.0.1.tgz#b968c6b0a04384324902e8bf1a5df32579a450fe"
-
 glob@7.0.5:
   version "7.0.5"
   resolved "https://registry.npmjs.org/glob/-/glob-7.0.5.tgz#b4202a69099bbb4d292a7c1b95b6682b67ebdc95"
@@ -235,10 +211,6 @@ glob@^7.0.5:
     once "^1.3.0"
     path-is-absolute "^1.0.0"
 
-graceful-fs@^4.1.2:
-  version "4.1.11"
-  resolved "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.1.11.tgz#0e8bdfe4d1ddb8854d64e04ea7c00e2a026e5658"
-
 "graceful-readlink@>= 1.0.0":
   version "1.0.1"
   resolved "https://registry.npmjs.org/graceful-readlink/-/graceful-readlink-1.0.1.tgz#4cafad76bc62f02fa039b2f94e9a3dd3a391a725"
@@ -267,16 +239,6 @@ heimdalljs@^0.2.3:
   dependencies:
     rsvp "~3.2.1"
 
-hosted-git-info@^2.1.4:
-  version "2.2.0"
-  resolved "https://registry.npmjs.org/hosted-git-info/-/hosted-git-info-2.2.0.tgz#7a0d097863d886c0fabbdcd37bf1758d8becf8a5"
-
-indent-string@^2.1.0:
-  version "2.1.0"
-  resolved "https://registry.npmjs.org/indent-string/-/indent-string-2.1.0.tgz#8e2d48348742121b4a8218b7a137e9a52049dc80"
-  dependencies:
-    repeating "^2.0.0"
-
 inflight@^1.0.4:
   version "1.0.6"
   resolved "https://registry.npmjs.org/inflight/-/inflight-1.0.6.tgz#49bd6331d7d02d0c09bc910a1075ba8165b56df9"
@@ -288,29 +250,13 @@ inherits@2:
   version "2.0.3"
   resolved "https://registry.npmjs.org/inherits/-/inherits-2.0.3.tgz#633c2c83e3da42a502f52466022480f4208261de"
 
-is-arrayish@^0.2.1:
-  version "0.2.1"
-  resolved "https://registry.npmjs.org/is-arrayish/-/is-arrayish-0.2.1.tgz#77c99840527aa8ecb1a8ba697b80645a7a926a9d"
-
 is-buffer@^1.0.2:
   version "1.1.4"
   resolved "https://registry.npmjs.org/is-buffer/-/is-buffer-1.1.4.tgz#cfc86ccd5dc5a52fa80489111c6920c457e2d98b"
 
-is-builtin-module@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.npmjs.org/is-builtin-module/-/is-builtin-module-1.0.0.tgz#540572d34f7ac3119f8f76c30cbc1b1e037affbe"
-  dependencies:
-    builtin-modules "^1.0.0"
-
-is-finite@^1.0.0:
-  version "1.0.2"
-  resolved "https://registry.npmjs.org/is-finite/-/is-finite-1.0.2.tgz#cc6677695602be550ef11e8b4aa6305342b6d0aa"
-  dependencies:
-    number-is-nan "^1.0.0"
-
-is-utf8@^0.2.0:
-  version "0.2.1"
-  resolved "https://registry.npmjs.org/is-utf8/-/is-utf8-0.2.1.tgz#4b0da1442104d1b336340e80797e865cf39f7d72"
+is-stream@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.npmjs.org/is-stream/-/is-stream-1.1.0.tgz#12d4a3dd4e68e0b79ceb8dbc84173ae80d91ca44"
 
 isexe@^1.1.1:
   version "1.1.2"
@@ -371,16 +317,6 @@ levn@~0.3.0:
     prelude-ls "~1.1.2"
     type-check "~0.3.2"
 
-load-json-file@^1.0.0:
-  version "1.1.0"
-  resolved "https://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz#956905708d58b4bab4c2261b04f59f31c99374c0"
-  dependencies:
-    graceful-fs "^4.1.2"
-    parse-json "^2.2.0"
-    pify "^2.0.0"
-    pinkie-promise "^2.0.0"
-    strip-bom "^2.0.0"
-
 lodash._baseassign@^3.0.0:
   version "3.2.0"
   resolved "https://registry.npmjs.org/lodash._baseassign/-/lodash._baseassign-3.2.0.tgz#8c38a099500f215ad09e59f1722fd0c52bfe0a4e"
@@ -432,31 +368,16 @@ longest@^1.0.1:
   version "1.0.1"
   resolved "https://registry.npmjs.org/longest/-/longest-1.0.1.tgz#30a0b2da38f73770e8294a0d22e6625ed77d0097"
 
-loud-rejection@^1.0.0:
-  version "1.6.0"
-  resolved "https://registry.npmjs.org/loud-rejection/-/loud-rejection-1.6.0.tgz#5b46f80147edee578870f086d04821cf998e551f"
+lru-cache@^4.0.0:
+  version "4.0.2"
+  resolved "https://registry.npmjs.org/lru-cache/-/lru-cache-4.0.2.tgz#1d17679c069cda5d040991a09dbc2c0db377e55e"
   dependencies:
-    currently-unhandled "^0.4.1"
-    signal-exit "^3.0.0"
+    pseudomap "^1.0.1"
+    yallist "^2.0.0"
 
-map-obj@^1.0.0, map-obj@^1.0.1:
-  version "1.0.1"
-  resolved "https://registry.npmjs.org/map-obj/-/map-obj-1.0.1.tgz#d933ceb9205d82bdcf4886f6742bdc2b4dea146d"
-
-meow@^3.4.0:
-  version "3.7.0"
-  resolved "https://registry.npmjs.org/meow/-/meow-3.7.0.tgz#72cb668b425228290abbfa856892587308a801fb"
-  dependencies:
-    camelcase-keys "^2.0.0"
-    decamelize "^1.1.2"
-    loud-rejection "^1.0.0"
-    map-obj "^1.0.1"
-    minimist "^1.1.3"
-    normalize-package-data "^2.3.4"
-    object-assign "^4.0.1"
-    read-pkg-up "^1.0.1"
-    redent "^1.0.0"
-    trim-newlines "^1.0.0"
+mem@^0.1.0:
+  version "0.1.1"
+  resolved "https://registry.npmjs.org/mem/-/mem-0.1.1.tgz#24df988c3102b03c074c1b296239c5b2e6647825"
 
 "minimatch@2 || 3", minimatch@^3.0.2:
   version "3.0.3"
@@ -468,10 +389,6 @@ minimist@0.0.8, minimist@~0.0.1:
   version "0.0.8"
   resolved "https://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz#857fcabfc3397d2625b8228262e86aa7a011b05d"
 
-minimist@^1.1.3:
-  version "1.2.0"
-  resolved "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz#a35008b20f41383eec1fb914f4cd5df79a264284"
-
 mkdirp@0.5.1, mkdirp@0.5.x, mkdirp@^0.5.0:
   version "0.5.1"
   resolved "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz#30057438eac6cf7f8c4767f38648d6697d75c903"
@@ -508,18 +425,11 @@ nopt@3.x:
   dependencies:
     abbrev "1"
 
-normalize-package-data@^2.3.2, normalize-package-data@^2.3.4:
-  version "2.3.6"
-  resolved "https://registry.npmjs.org/normalize-package-data/-/normalize-package-data-2.3.6.tgz#498fa420c96401f787402ba21e600def9f981fff"
+npm-run-path@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.npmjs.org/npm-run-path/-/npm-run-path-1.0.0.tgz#f5c32bf595fe81ae927daec52e82f8b000ac3c8f"
   dependencies:
-    hosted-git-info "^2.1.4"
-    is-builtin-module "^1.0.0"
-    semver "2 || 3 || 4 || 5"
-    validate-npm-package-license "^3.0.1"
-
-number-is-nan@^1.0.0:
-  version "1.0.1"
-  resolved "https://registry.npmjs.org/number-is-nan/-/number-is-nan-1.0.1.tgz#097b602b53422a522c1afb8790318336941a011d"
+    path-key "^1.0.0"
 
 object-assign@^4.0.1:
   version "4.1.1"
@@ -549,80 +459,26 @@ optionator@^0.8.1:
     type-check "~0.3.2"
     wordwrap "~1.0.0"
 
-parse-json@^2.2.0:
-  version "2.2.0"
-  resolved "https://registry.npmjs.org/parse-json/-/parse-json-2.2.0.tgz#f480f40434ef80741f8469099f8dea18f55a4dc9"
-  dependencies:
-    error-ex "^1.2.0"
-
-path-exists@^2.0.0:
-  version "2.1.0"
-  resolved "https://registry.npmjs.org/path-exists/-/path-exists-2.1.0.tgz#0feb6c64f0fc518d9a754dd5efb62c7022761f4b"
-  dependencies:
-    pinkie-promise "^2.0.0"
-
 path-is-absolute@^1.0.0:
   version "1.0.1"
   resolved "https://registry.npmjs.org/path-is-absolute/-/path-is-absolute-1.0.1.tgz#174b9268735534ffbc7ace6bf53a5a9e1b5c5f5f"
 
-path-type@^1.0.0:
-  version "1.1.0"
-  resolved "https://registry.npmjs.org/path-type/-/path-type-1.1.0.tgz#59c44f7ee491da704da415da5a4070ba4f8fe441"
-  dependencies:
-    graceful-fs "^4.1.2"
-    pify "^2.0.0"
-    pinkie-promise "^2.0.0"
-
-pify@^2.0.0:
-  version "2.3.0"
-  resolved "https://registry.npmjs.org/pify/-/pify-2.3.0.tgz#ed141a6ac043a849ea588498e7dca8b15330e90c"
-
-pinkie-promise@^2.0.0:
-  version "2.0.1"
-  resolved "https://registry.npmjs.org/pinkie-promise/-/pinkie-promise-2.0.1.tgz#2135d6dfa7a358c069ac9b178776288228450ffa"
-  dependencies:
-    pinkie "^2.0.0"
-
-pinkie@^2.0.0:
-  version "2.0.4"
-  resolved "https://registry.npmjs.org/pinkie/-/pinkie-2.0.4.tgz#72556b80cfa0d48a974e80e77248e80ed4f7f870"
+path-key@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.npmjs.org/path-key/-/path-key-1.0.0.tgz#5d53d578019646c0d68800db4e146e6bdc2ac7af"
 
 prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
 
-read-pkg-up@^1.0.1:
-  version "1.0.1"
-  resolved "https://registry.npmjs.org/read-pkg-up/-/read-pkg-up-1.0.1.tgz#9d63c13276c065918d57f002a57f40a1b643fb02"
-  dependencies:
-    find-up "^1.0.0"
-    read-pkg "^1.0.0"
-
-read-pkg@^1.0.0:
-  version "1.1.0"
-  resolved "https://registry.npmjs.org/read-pkg/-/read-pkg-1.1.0.tgz#f5ffaa5ecd29cb31c0474bca7d756b6bb29e3f28"
-  dependencies:
-    load-json-file "^1.0.0"
-    normalize-package-data "^2.3.2"
-    path-type "^1.0.0"
-
-redent@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.npmjs.org/redent/-/redent-1.0.0.tgz#cf916ab1fd5f1f16dfb20822dd6ec7f730c2afde"
-  dependencies:
-    indent-string "^2.1.0"
-    strip-indent "^1.0.1"
+pseudomap@^1.0.1:
+  version "1.0.2"
+  resolved "https://registry.npmjs.org/pseudomap/-/pseudomap-1.0.2.tgz#f052a28da70e618917ef0a8ac34c1ae5a68286b3"
 
 repeat-string@^1.5.2:
   version "1.6.1"
   resolved "https://registry.npmjs.org/repeat-string/-/repeat-string-1.6.1.tgz#8dcae470e1c88abc2d600fff4a776286da75e637"
 
-repeating@^2.0.0:
-  version "2.0.1"
-  resolved "https://registry.npmjs.org/repeating/-/repeating-2.0.1.tgz#5214c53a926d3552707527fbab415dbc08d06dda"
-  dependencies:
-    is-finite "^1.0.0"
-
 resolve@1.1.x:
   version "1.1.7"
   resolved "https://registry.npmjs.org/resolve/-/resolve-1.1.7.tgz#203114d82ad2c5ed9e8e0411b3932875e889e97b"
@@ -647,14 +503,6 @@ rsvp@~3.2.1:
   version "3.2.1"
   resolved "https://registry.npmjs.org/rsvp/-/rsvp-3.2.1.tgz#07cb4a5df25add9e826ebc67dcc9fd89db27d84a"
 
-"semver@2 || 3 || 4 || 5":
-  version "5.3.0"
-  resolved "https://registry.npmjs.org/semver/-/semver-5.3.0.tgz#9b2ce5d3de02d17c6012ad326aa6b4d0cf54f94f"
-
-signal-exit@^3.0.0:
-  version "3.0.2"
-  resolved "https://registry.npmjs.org/signal-exit/-/signal-exit-3.0.2.tgz#b5fdc08f1287ea1178628e415e25132b73646c6d"
-
 source-map@^0.4.4:
   version "0.4.4"
   resolved "https://registry.npmjs.org/source-map/-/source-map-0.4.4.tgz#eba4f5da9c0dc999de68032d8b4f76173652036b"
@@ -671,20 +519,6 @@ source-map@~0.5.1:
   version "0.5.6"
   resolved "https://registry.npmjs.org/source-map/-/source-map-0.5.6.tgz#75ce38f52bf0733c5a7f0c118d81334a2bb5f412"
 
-spdx-correct@~1.0.0:
-  version "1.0.2"
-  resolved "https://registry.npmjs.org/spdx-correct/-/spdx-correct-1.0.2.tgz#4b3073d933ff51f3912f03ac5519498a4150db40"
-  dependencies:
-    spdx-license-ids "^1.0.2"
-
-spdx-expression-parse@~1.0.0:
-  version "1.0.4"
-  resolved "https://registry.npmjs.org/spdx-expression-parse/-/spdx-expression-parse-1.0.4.tgz#9bdf2f20e1f40ed447fbe273266191fced51626c"
-
-spdx-license-ids@^1.0.2:
-  version "1.2.2"
-  resolved "https://registry.npmjs.org/spdx-license-ids/-/spdx-license-ids-1.2.2.tgz#c9df7a3424594ade6bd11900d596696dc06bac57"
-
 sprintf-js@~1.0.2:
   version "1.0.3"
   resolved "https://registry.npmjs.org/sprintf-js/-/sprintf-js-1.0.3.tgz#04e6926f662895354f3dd015203633b857297e2c"
@@ -693,17 +527,9 @@ stat-mode@^0.2.1:
   version "0.2.2"
   resolved "https://registry.npmjs.org/stat-mode/-/stat-mode-0.2.2.tgz#e6c80b623123d7d80cf132ce538f346289072502"
 
-strip-bom@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.npmjs.org/strip-bom/-/strip-bom-2.0.0.tgz#6219a85616520491f35788bdbf1447a99c7e6b0e"
-  dependencies:
-    is-utf8 "^0.2.0"
-
-strip-indent@^1.0.1:
-  version "1.0.1"
-  resolved "https://registry.npmjs.org/strip-indent/-/strip-indent-1.0.1.tgz#0c7962a6adefa7bbd4ac366460a638552ae1a0a2"
-  dependencies:
-    get-stdin "^4.0.1"
+strip-eof@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.npmjs.org/strip-eof/-/strip-eof-1.0.0.tgz#bb43ff5598a6eb05d89b59fcd129c983313606bf"
 
 supports-color@3.1.2:
   version "3.1.2"
@@ -721,10 +547,6 @@ supports-color@^3.1.0:
   version "2.0.1"
   resolved "https://registry.npmjs.org/textextensions/-/textextensions-2.0.1.tgz#be8cf22d65379c151319f88f0335ad8f667abdca"
 
-trim-newlines@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.npmjs.org/trim-newlines/-/trim-newlines-1.0.0.tgz#5887966bb582a4503a41eb524f7d35011815a613"
-
 type-check@~0.3.2:
   version "0.3.2"
   resolved "https://registry.npmjs.org/type-check/-/type-check-0.3.2.tgz#5884cab512cf1d355e3fb784f30804b2b520db72"
@@ -751,20 +573,14 @@ uglify-to-browserify@~1.0.0:
   version "1.0.2"
   resolved "https://registry.npmjs.org/uglify-to-browserify/-/uglify-to-browserify-1.0.2.tgz#6e0924d6bda6b5afe349e39a6d632850a0f882b7"
 
-username@^1.0.1:
-  version "1.0.1"
-  resolved "https://registry.npmjs.org/username/-/username-1.0.1.tgz#e1f72295e3e58e06f002c6327ce06897a99cd67f"
-  dependencies:
-    meow "^3.4.0"
-
-validate-npm-package-license@^3.0.1:
-  version "3.0.1"
-  resolved "https://registry.npmjs.org/validate-npm-package-license/-/validate-npm-package-license-3.0.1.tgz#2804babe712ad3379459acfbe24746ab2c303fbc"
+username@^2.3.0:
+  version "2.3.0"
+  resolved "https://registry.npmjs.org/username/-/username-2.3.0.tgz#ba37dd53ac7d6225e77730fdd79244f1fc058e1e"
   dependencies:
-    spdx-correct "~1.0.0"
-    spdx-expression-parse "~1.0.0"
+    execa "^0.4.0"
+    mem "^0.1.0"
 
-which@^1.1.1:
+which@^1.1.1, which@^1.2.8:
   version "1.2.12"
   resolved "https://registry.npmjs.org/which/-/which-1.2.12.tgz#de67b5e450269f194909ef23ece4ebe416fa1192"
   dependencies:
@@ -790,6 +606,10 @@ wrappy@1:
   version "1.0.2"
   resolved "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz#b5243d8f3ec1aa35f1364605bc0d1036e30ab69f"
 
+yallist@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.npmjs.org/yallist/-/yallist-2.0.0.tgz#306c543835f09ee1a4cb23b7bce9ab341c91cdd4"
+
 yargs@~3.10.0:
   version "3.10.0"
   resolved "https://registry.npmjs.org/yargs/-/yargs-3.10.0.tgz#f7ee7bd857dd7c1d2d38c0e74efbd681d1431fd1"