Bump codecov from 3.0.0 to 3.6.5

Bumps [codecov](https://github.com/codecov/codecov-node) from 3.0.0 to 3.6.5.
- [Release notes](https://github.com/codecov/codecov-node/releases)
- [Commits](https://github.com/codecov/codecov-node/commits)

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

Author: dependabot[bot]