Update pytest-flake8 to 1.0.3

[pyup-bot]

This PR updates pytest-flake8 from 1.0.2 to 1.0.3.

Changelog

1.0.3

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- Don't use long deprecated functions from pytest, broke with pytest 4.1.0
- Fix typo that caused some tests to not run as expected
- Run Travis CI tests against Python 3.7, and fix some issues with current tox

Links

• PyPI: https://pypi.org/project/pytest-flake8
• Changelog: https://pyup.io/changelogs/pytest-flake8/
• Repo: https://github.com/tholo/pytest-flake8

[coveralls]

Coverage increased (+0.07%) to 84.143% when pulling aa7129c on pyup-update-pytest-flake8-1.0.2-to-1.0.3 into 37d28cc on master.