Bump coveralls from 2.1.1 to 2.1.2

Bumps [coveralls](https://github.com/coveralls-clients/coveralls-python) from 2.1.1 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@2.1.1...2.1.2)

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

requirements.txt

@@ -1,6 +1,6 @@
 bandit==1.6.2
 coverage==5.2.1
-coveralls==2.1.1
+coveralls==2.1.2
 Flask==1.1.2
 Flask-SSLify==0.1.5
 Flask-Testing==0.8.0