Merge pull request #39 from yargs/greenkeeper-mocha-3.0.0

Update mocha to version 3.0.0 🚀

Author: maxrimue

package.json

@@ -53,7 +53,7 @@
     "chai": "^3.5.0",
     "chalk": "^1.1.2",
     "coveralls": "^2.11.8",
-    "mocha": "^2.4.5",
+    "mocha": "^3.0.0",
     "nyc": "^7.0.0",
     "standard": "^7.0.1",
     "standard-version": "^2.1.2"