chore(package): update mocha to version 6.1.0

Closes #2

Author: greenkeeper[bot]

package.json

@@ -36,7 +36,7 @@
     "assume": "~1.5.0",
     "ejs": "~2.5.2",
     "istanbul": "~0.4.5",
-    "mocha": "~3.1.2",
+    "mocha": "~6.1.0",
     "pre-commit": "~1.2.0"
   },
   "dependencies": {