chore(package): update mocha to version 4.0.0

Author: greenkeeper[bot]

package.json

@@ -44,7 +44,7 @@
     "gulp-typescript": "^3.1.4",
     "harmonize": "^2.0.0",
     "inversify": "^4.0.0",
-    "mocha": "^3.0.0",
+    "mocha": "^4.0.0",
     "publish-please": "^2.1.4",
     "reflect-metadata": "^0.1.9",
     "run-sequence": "^1.2.0",