Bump codecov from 2.3.1 to 3.7.1

Bumps [codecov](https://github.com/codecov/codecov-node) from 2.3.1 to 3.7.1.
- [Release notes](https://github.com/codecov/codecov-node/releases)
- [Commits](codecov/codecov-node@v2.3.1...v3.7.1)

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

Author: dependabot[bot]