Bump codecov from 2.3.1 to 3.8.3

Bumps [codecov](https://github.com/codecov/codecov-node) from 2.3.1 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](codecov/codecov-node@v2.3.1...v3.8.3)

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

Signed-off-by: dependabot[bot] <[email protected]>