chore(package): update mocha to version 5.0.5

Closes #6

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
   },
   "devDependencies": {
     "chai": "^4.1.2",
-    "mocha": "^4.0.0",
+    "mocha": "^5.0.5",
     "standard": "^10.0.3"
   }
 }