Bump codecov from 3.5.0 to 3.8.3

Bumps [codecov](https://github.com/codecov/codecov-node) from 3.5.0 to 3.8.3.
- [Release notes](https://github.com/codecov/codecov-node/releases)
- [Changelog](https://github.com/codecov/codecov-node/blob/master/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-node/commits/v3.8.3)

---
updated-dependencies:
- dependency-name: codecov
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -85,7 +85,7 @@
     "@typescript-eslint/parser": "1.12.0",
     "babel-core": "6.26.3",
     "babel-plugin-transform-react-remove-prop-types": "0.4.24",
-    "codecov": "3.5.0",
+    "codecov": "3.8.3",
     "cp-cli": "2.0.0",
     "cross-env": "5.2.0",
     "del-cli": "2.0.0",