fix(package): update mocha to version 6.2.1

Closes #42

Author: greenkeeper[bot]

package.json

@@ -37,7 +37,7 @@
     "errorhandler": "latest",
     "inversify": "^4.11.1",
     "method-override": "^2.3.10",
-    "mocha": "^5.0.1",
+    "mocha": "^6.2.1",
     "mocha-typescript": "^1.1.12",
     "morgan": "^1.9.0",
     "path": "^0.12.7",