Update dev-dependencies

Author: wooorm

package.json

@@ -28,13 +28,13 @@
   },
   "devDependencies": {
     "browserify": "^16.0.0",
-    "nyc": "^11.0.2",
+    "nyc": "^12.0.0",
     "prettier": "^1.12.1",
     "remark-cli": "^5.0.0",
     "remark-preset-wooorm": "^4.0.0",
     "tape": "^4.0.0",
     "tinyify": "^2.4.3",
-    "xo": "^0.20.0"
+    "xo": "^0.22.0"
   },
   "scripts": {
     "format": "remark . -qfo && prettier --write '**/*.js' && xo --fix",