Bump coverage from 5.0.3 to 5.1
Bumps [coverage](https://github.com/nedbat/coveragepy) from 5.0.3 to 5.1.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](https://github.com/nedbat/coveragepy/compare/coverage-5.0.3...coverage-5.1)
Signed-off-by: dependabot-preview[bot] <[email protected]>
dependabot-preview[bot]