Update mocha

Author: blakeembrey

package.json

@@ -28,6 +28,6 @@
   "devDependencies": {
     "chai": "^4.0.2",
     "istanbul": "^0.4.5",
-    "mocha": "^3.3.0"
+    "mocha": "^4.0.1"
   }
 }