chore(package): update coveralls to version 3.0.12

Closes #7

Author: greenkeeper[bot]

package.json

@@ -6,7 +6,7 @@
   "dependencies": {},
   "devDependencies": {
     "chai": "^4.0.1",
-    "coveralls": "^2.11.16",
+    "coveralls": "^3.0.12",
     "mocha": "^5.0.0",
     "nyc": "^13.2.0",
     "snazzy": "^7.0.0",