chore(package): update codecov to version 3.1.0 (#654)

Author: greenkeeper[bot]

package.json

@@ -49,7 +49,7 @@
     "babel-plugin-minify-dead-code-elimination": "0.4.3",
     "babel-plugin-transform-inline-environment-variables": "0.4.3",
     "browserify": "16.2.2",
-    "codecov": "3.0.4",
+    "codecov": "3.1.0",
     "eslint": "^5.3.0",
     "eslint-plugin-flowtype": "^2.50.0",
     "express": "^4.16.3",