chore(package): update mocha to version 6.0.0

Author: greenkeeper[bot]

package.json

@@ -24,7 +24,7 @@
     "eslint": "^5.0.0",
     "eslint-config-toboid": "2.0.0",
     "lodash": "^4.17.9",
-    "mocha": "^5.0.0",
+    "mocha": "^6.0.0",
     "nyc": "^13.2.0"
   },
   "dependencies": {