chore(package): update coveralls to version 2.11.8

http://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -33,7 +33,7 @@
     "babel-preset-es2015": "6.5.0",
     "babel-register": "6.5.2",
     "chai": "3.5.0",
-    "coveralls": "2.11.6",
+    "coveralls": "2.11.8",
     "cz-conventional-changelog": "1.1.5",
     "in-publish": "2.0.0",
     "mocha": "2.4.5",