Merge pull request #877 from graphql/greenkeeper/mocha-3.4.2

Update mocha to the latest version 🚀

Author: wincent

package.json

@@ -75,7 +75,7 @@
     "eslint-plugin-flowtype": "2.33.0",
     "flow-bin": "0.46.0",
     "isparta": "4.0.0",
-    "mocha": "3.4.1",
+    "mocha": "3.4.2",
     "sane": "1.7.0"
   }
 }