Merge pull request #774 from graphql/greenkeeper/coveralls-2.13.0

Update coveralls to the latest version 🚀

Author: wincent

package.json

@@ -66,7 +66,7 @@
     "chai": "3.5.0",
     "chai-json-equal": "0.0.1",
     "chai-subset": "1.5.0",
-    "coveralls": "2.12.0",
+    "coveralls": "2.13.0",
     "eslint": "3.18.0",
     "eslint-plugin-babel": "4.1.1",
     "eslint-plugin-flowtype": "2.30.4",