Bump coveralls from 2.0.0 to 2.1.2

Bumps [coveralls](https://github.com/coveralls-clients/coveralls-python) from 2.0.0 to 2.1.2.
- [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@2.0.0...2.1.2)

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

requirements-test.txt

@@ -1,3 +1,3 @@
 tox==3.15.0
-coveralls==2.0.0
+coveralls==2.1.2
 pre-commit==2.4.0