Bump coveralls from 1.8.2 to 2.1.1

Bumps [coveralls](https://github.com/coveralls-clients/coveralls-python) from 1.8.2 to 2.1.1.
- [Release notes](https://github.com/coveralls-clients/coveralls-python/releases)
- [Changelog](https://github.com/coveralls-clients/coveralls-python/blob/master/CHANGELOG.md)
- [Commits](TheKevJames/coveralls-python@1.8.2...2.1.1)

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