Update pytest-runner to 5.0

[pyup-bot]

This PR updates pytest-runner from 4.4 to 5.0.

Changelog

5.0

===

* Packaging refresh, released again.

4.5.1

=====

* 48: Revert changes from 4.5 - restoring project to the
state at 4.4.

4.5

===

(Pulled from PyPI due to 43 and 48)

* Packaging (skeleton) refresh, including adoption of
`black <https://pypi.org/project/black>`_ for style.

Links

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

[pyup-bot]

Closing this in favor of #15