Bump coveralls from 1.7.0 to 3.0.0

Bumps [coveralls](https://github.com/coveralls-clients/coveralls-python) from 1.7.0 to 3.0.0.
- [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@1.7.0...3.0.0)

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

requirements-dev.txt

@@ -4,4 +4,4 @@ coverage==4.5.3
 pytest==4.4.0
 pytest-cov==2.6.1
 responses==0.10.6
-coveralls==1.7.0
+coveralls==3.0.0