chore(package): update coveralls to version 2.11.9

http://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -27,7 +27,7 @@
   },
   "homepage": "https://github.com/ManRueda/zip-mapper#readme",
   "devDependencies": {
-    "coveralls": "2.11.8",
+    "coveralls": "2.11.9",
     "grunt": "0.4.5",
     "grunt-contrib-jshint": "1.0.0",
     "grunt-jscs": "2.8.0",