Update flaky to 3.8.1

[pyup-bot]

This PR updates flaky from 3.7.0 to 3.8.1.

Changelog

3.8.0

++++++++++++++++++

- nose support has been removed.
- Python 3.12 supported.
- Bugfixes

Links

• PyPI: https://pypi.org/project/flaky
• Changelog: https://data.safetycli.com/changelogs/flaky/
• Repo: https://github.com/box/flaky