Update vulture to 0.27

[pyup-bot]

This PR updates vulture from 0.26 to 0.27.

Changelog

0.27

-----------------
* Report ``while (True): ... else: ...`` as unreachable (thanks RJ722).
* Whitelist Mock.return_value and Mock.side_effect in unittest.mock module.
* Drop support for Python 2.6 and 3.3.
* Improve documentation and test coverage (thanks RJ722).

Links

• PyPI: https://pypi.org/project/vulture
• Changelog: https://pyup.io/changelogs/vulture/
• Repo: https://github.com/jendrikseipp/vulture

[coveralls]

Coverage remained the same at 96.281% when pulling c871088 on pyup-update-vulture-0.26-to-0.27 into a59bd3f on master.

[pyup-bot]

Closing this in favor of #48