chore(package): update coveralls to version 2.11.12

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -27,7 +27,7 @@
     "check"
   ],
   "devDependencies": {
-    "coveralls": "^2.11.4",
+    "coveralls": "^2.11.12",
     "eslint-config-mongodb-js": "^2.0.0",
     "istanbul": "^0.4.0",
     "lodash.defaults": "^4.0.1",