Drop the moment dependency

It takes up 3.1 MB on disk.

I also switched from Z to UTC as it’s more user-friendly.

lib/complexValues/date.js

@@ -1,6 +1,6 @@
 'use strict'
 
-const moment = require('moment')
+const dateTime = require('date-time')
 
 const constants = require('../constants')
 const formatUtils = require('../formatUtils')
@@ -28,9 +28,12 @@ exports.tag = tag
 function formatDate (date) {
   // Always format in UTC. The local timezone shouldn't be used since it's most
   // likely different from that of CI servers.
-  const utc = moment.utc(date)
-  const ms = utc.milliseconds()
-  return utc.format(`YYYY-MM-DD HH:mm:ss [${ms > 0 ? `${ms}ms Z` : 'Z'}]`)
+  return dateTime({
+    date,
+    local: false,
+    showTimeZone: true,
+    showMilliseconds: true
+  })
 }
 
 class DateValue extends object.ObjectValue {

package.json

@@ -27,6 +27,7 @@
   },
   "homepage": "https://github.com/concordancejs/concordance#readme",
   "dependencies": {
+    "date-time": "^2.1.0",
     "esutils": "^2.0.2",
     "fast-diff": "^1.1.1",
     "function-name-support": "^0.2.0",
@@ -35,7 +36,6 @@
     "lodash.flattendeep": "^4.4.0",
     "lodash.merge": "^4.6.0",
     "md5-hex": "^2.0.0",
-    "moment": "^2.18.1",
     "semver": "^5.3.0",
     "well-known-symbols": "^1.0.0"
   },

test/snapshots/diff.js.md

@@ -432,8 +432,8 @@ Generated by [AVA](https://ava.li).
 
 > Snapshot 1
 
-    `%diffGutters.actual#- %%object.ctor.open%Date%object.ctor.close% %date.value.open%1969-07-20 20:17:40 Z%date.value.close% %object.openBracket#{%%object.closeBracket#}%␊
-    %diffGutters.expected#+ %%object.ctor.open%Date%object.ctor.close% %date.value.open%1969-07-21 20:17:40 Z%date.value.close% %object.openBracket#{%␊
+    `%diffGutters.actual#- %%object.ctor.open%Date%object.ctor.close% %date.value.open%1969-07-20 20:17:40 UTC%date.value.close% %object.openBracket#{%%object.closeBracket#}%␊
+    %diffGutters.expected#+ %%object.ctor.open%Date%object.ctor.close% %date.value.open%1969-07-21 20:17:40 UTC%date.value.close% %object.openBracket#{%␊
     %diffGutters.expected#+ %  foo%property.separator#: %%string.line.open#'%%string.open%bar%string.close%%string.line.close#'%%property.after#,%␊
     %diffGutters.expected#+ %%object.closeBracket#}%`
 

test/snapshots/format.js.md

@@ -463,7 +463,7 @@ Generated by [AVA](https://ava.li).
 
 > Snapshot 1
 
-    '%object.ctor.open%Date%object.ctor.close% %date.value.open%1969-07-20 20:17:40 12ms Z%date.value.close% %object.openBracket#{%%object.closeBracket#}%'
+    '%object.ctor.open%Date%object.ctor.close% %date.value.open%1969-07-20 20:17:40 12ms UTC%date.value.close% %object.openBracket#{%%object.closeBracket#}%'
 
 > Snapshot 2
 
@@ -473,7 +473,7 @@ Generated by [AVA](https://ava.li).
 
 > Snapshot 1
 
-    `%object.ctor.open%Date%object.ctor.close% %date.value.open%1969-07-20 20:17:40 Z%date.value.close% %object.openBracket#{%␊
+    `%object.ctor.open%Date%object.ctor.close% %date.value.open%1969-07-20 20:17:40 UTC%date.value.close% %object.openBracket#{%␊
       foo%property.separator#: %%string.line.open#'%%string.open%bar%string.close%%string.line.close#'%%property.after#,%␊
     %object.closeBracket#}%`
 
@@ -813,7 +813,7 @@ Generated by [AVA](https://ava.li).
 
 > Snapshot 3
 
-    '%object.ctor.open%Baz%object.ctor.close% %object.secondaryStringTag.open#@%Date%object.secondaryStringTag.close% %date.value.open%1969-07-20 20:17:40 Z%date.value.close% %object.openBracket#{%%object.closeBracket#}%'
+    '%object.ctor.open%Baz%object.ctor.close% %object.secondaryStringTag.open#@%Date%object.secondaryStringTag.close% %date.value.open%1969-07-20 20:17:40 UTC%date.value.close% %object.openBracket#{%%object.closeBracket#}%'
 
 > Snapshot 4
 

test/snapshots/max-depth.js.md

@@ -22,8 +22,8 @@ Generated by [AVA](https://ava.li).
           two: {␊
             arr: [],␊
             arr2: Array [ … ],␊
-            date: Date 1969-07-20 20:17:40 Z {},␊
-            date2: Date 1969-07-20 20:17:40 Z { … },␊
+            date: Date 1969-07-20 20:17:40 UTC {},␊
+            date2: Date 1969-07-20 20:17:40 UTC { … },␊
             error: Error { … },␊
             fn: Function fn {},␊
             fn2: Function { … },␊
@@ -71,8 +71,8 @@ Generated by [AVA](https://ava.li).
         two: {␊
           arr: [],␊
           arr2: Array [ … ],␊
-          date: Date 1969-07-20 20:17:40 Z {},␊
-          date2: Date 1969-07-20 20:17:40 Z { … },␊
+          date: Date 1969-07-20 20:17:40 UTC {},␊
+          date2: Date 1969-07-20 20:17:40 UTC { … },␊
           error: Error { … },␊
           fn: Function fn {},␊
           fn2: Function { … },␊