Update coveralls to the latest version 🚀 (#8)

Author: greenkeeper[bot]

package.json

@@ -48,7 +48,7 @@
     "babel-cli": "^6.9.0",
     "babel-plugin-add-module-exports": "^0.2.1",
     "babel-preset-es2015": "^6.9.0",
-    "coveralls": "^2.11.9",
+    "coveralls": "^3.0.0",
     "eslint-config-xo-lukechilds": "^1.0.0",
     "nyc": "^11.0.2",
     "window": "^4.1.0",