chore(package): update coveralls to version 3.1.0

Closes #15

Author: greenkeeper[bot]

package.json

@@ -59,7 +59,7 @@
     "babel-register": "^6.16.3",
     "commitizen": "^2.8.6",
     "conventional-changelog-cli": "^1.2.0",
-    "coveralls": "^2.11.14",
+    "coveralls": "^3.1.0",
     "cz-conventional-changelog": "^1.2.0",
     "eslint": "^3.7.1",
     "eslint-plugin-ava": "^4.0.0",