chore(package): update mocha to version 6.2.0

Closes #22

Author: greenkeeper[bot]

package.json

@@ -13,7 +13,7 @@
     "eslint": "^4.1.1",
     "eslint-config-democracyos": "^2.0.0",
     "eslint-plugin-mocha": "~4.11.0",
-    "mocha": "~3.5.0",
+    "mocha": "~6.2.0",
     "mocha-eslint": "~3.0.1"
   },
   "files": [