Update dependency mocha to v5

Author: renovate-bot

package-lock.json

@@ -33,7 +33,7 @@
     "eslint": "3.19.0",
     "eslint-config-airbnb-base": "11.3.2",
     "eslint-plugin-import": "2.8.0",
-    "mocha": "3.5.3"
+    "mocha": "5.1.1"
   },
   "engines": {
     "node": ">=0.10",