chore(package): update codecov to version 3.4.0

Closes #211

Author: greenkeeper[bot]

package.json

@@ -68,7 +68,7 @@
     "babel-preset-es2015": "6.24.1",
     "babel-preset-stage-0": "6.24.1",
     "babel-register": "6.26.0",
-    "codecov": "3.0.1",
+    "codecov": "3.4.0",
     "commitizen": "2.10.1",
     "cz-conventional-changelog": "2.1.0",
     "dont-break": "1.13.4",