fix(package): update moment to version 2.18.1

Closes #2098

https://greenkeeper.io/

package.json

@@ -188,7 +188,7 @@
     "isomorphic-fetch": "2.2.1",
     "jed": "1.1.1",
     "jsdom": "9.11.0",
-    "moment": "2.17.1",
+    "moment": "2.18.1",
     "mozilla-tabzilla": "0.5.1",
     "mozilla-version-comparator": "1.0.2",
     "normalize.css": "5.0.0",