Bump coveralls from 1.8.2 to 1.9.0

Bumps [coveralls](https://github.com/coveralls-clients/coveralls-python) from 1.8.2 to 1.9.0.
- [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...1.9.0)

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

requirements-dev.txt

@@ -3,7 +3,7 @@
 # Now for the dev specific stuff
 black==19.10b0
 coverage==4.5.4
-coveralls==1.8.2
+coveralls==1.9.0
 flake8==3.7.9
 nose==1.3.7
 requests-mock==1.7.0