chore(package): update mocha to version 4.0.0

Closes #10

Author: greenkeeper[bot]

package.json

@@ -39,7 +39,7 @@
     "loopback": "3.8.0",
     "loopback-boot": "2.24.0",
     "loopback-component-explorer": "4.2.0",
-    "mocha": "3.4.2",
+    "mocha": "4.0.0",
     "nyc": "11.0.2",
     "semantic-release": "6.3.6",
     "strong-error-handler": "2.1.0"