Update codecov to the latest version 🚀 (#818)

* chore(package): update codecov to version 3.4.0

* chore(package): update lockfile package-lock.json

Author: greenkeeper[bot]

package-lock.json

@@ -50,7 +50,7 @@
     "babel-plugin-minify-dead-code-elimination": "0.5.0",
     "babel-plugin-transform-inline-environment-variables": "0.4.3",
     "browserify": "16.2.3",
-    "codecov": "3.3.0",
+    "codecov": "3.4.0",
     "eslint": "5.16.0",
     "eslint-plugin-flowtype": "3.8.1",
     "express": "4.16.4",