chore(package): update coveralls to version 2.11.13

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -24,7 +24,7 @@
   "devDependencies": {
     "browserify": "13.0.1",
     "chai": "3.5.0",
-    "coveralls": "2.11.9",
+    "coveralls": "2.11.13",
     "istanbul": "0.4.4",
     "mocha": "3.1.0",
     "sinon": "1.17.4",