Merge pull request #34 from zrrrzzt/greenkeeper/coveralls-2.13.1

Update coveralls to the latest version 🚀

package.json

@@ -32,7 +32,7 @@
     "coveralls": "tap --cov --coverage-report=lcov test/**/*.js && cat coverage/lcov.info | coveralls"
   },
   "devDependencies": {
-    "coveralls": "2.13.0",
+    "coveralls": "2.13.1",
     "nsp": "2.6.3",
     "standard": "10.0.2",
     "tap": "10.3.2"