chore(package): update codecov to version 3.1.0 (#16)

Author: greenkeeper[bot]

package.json

@@ -29,7 +29,7 @@
     "probot": "7.1.1"
   },
   "devDependencies": {
-    "codecov": "3.0.4",
+    "codecov": "3.1.0",
     "jest": "23.4.1",
     "nodemon": "1.18.4",
     "semantic-release": "15.9.12",