chore(package): update codecov to version 3.0.0

Author: greenkeeper[bot]

package.json

@@ -96,7 +96,7 @@
     "babel-plugin-transform-flow-strip-types": "^6.22.0",
     "babel-preset-env": "^1.6.0",
     "babel-preset-flow": "^6.23.0",
-    "codecov": "^2.3.0",
+    "codecov": "^3.0.0",
     "coveralls": "^3.0.0",
     "eslint": "^4.7.2",
     "eslint-config-xo-space": "^0.16.0",