chore(package): update mocha to version 6.0.1

Closes #30

Author: greenkeeper[bot]

package.json

@@ -21,7 +21,7 @@
     "browserify": "^16.1.1",
     "cheerio": ">=0.20.0",
     "markdown-it": ">=7.0.0",
-    "mocha": "^5.0.2",
+    "mocha": "^6.0.1",
     "uglify": "*"
   },
   "keywords": [