chore(package): update gulp-mocha to version 4.0.0

https://greenkeeper.io/

Author: greenkeeper[bot]

package.json

@@ -23,7 +23,7 @@
     "express": "4.14.0",
     "express-session": "1.14.2",
     "gulp": "3.9.1",
-    "gulp-mocha": "3.0.1",
+    "gulp-mocha": "4.0.0",
     "gulp-jscs": "4.0.0",
     "istanbul": "0.4.5",
     "jscs": "3.0.7",