chore(package): update mocha to version 3.1.2 (#2289)

https://greenkeeper.io/ [skip ci]

Author: greenkeeperio-bot

package.json

@@ -77,7 +77,7 @@
     "lazypipe": "^1.0.1",
     "merge-stream": "^1.0.0",
     "minimatch": "^3.0.2",
-    "mocha": "^3.0.0",
+    "mocha": "^3.1.2",
     "q": "^1.0.1",
     "recursive-readdir": "^2.0.0",
     "run-sequence": "^1.2.1",