chore(package): update mocha to version 5.1.0

Closes #10

Author: greenkeeper[bot]

package.json

@@ -34,7 +34,7 @@
   "devDependencies": {
     "assume": "1.5.0",
     "istanbul": "0.4.5",
-    "mocha": "3.5.0",
+    "mocha": "5.1.0",
     "pre-commit": "1.2.0"
   },
   "dependencies": {