chore(package): update codecov to version 3.1.0

Closes #11

Author: greenkeeper[bot]

package.json

@@ -23,7 +23,7 @@
     "grunt-contrib-connect": "^1.0.2",
     "grunt-parts": "^0.5.6",
     "ajv": "^5.4.0",
-    "codecov": "^1.0.1",
+    "codecov": "^3.1.0",
     "eslint": "^4.11.0",
     "eslint-config-airbnb-base": "^10.0.1",
     "eslint-plugin-import": "^2.2.0",