chore(package): update mocha to version 3.2.0

https://greenkeeper.io/

package.json

@@ -35,7 +35,7 @@
   "devDependencies": {
     "assume": "~1.4.1",
     "istanbul": "~0.4.5",
-    "mocha": "~3.1.2",
+    "mocha": "~3.2.0",
     "pre-commit": "~1.1.3"
   }
 }