Running tests with Python 3.8 fails

[carlosperate]

All CI jobs with Python 3.8+ are now failing, without any changes in this codebase to trigger this.

As an example, the latest commit in main is: 5e4067b

When it was pushed, all tests passed: https://github.com/mu-editor/mu/actions/runs/7504275586/attempts/1
I've restarted the jobs and Python 3.8 fails: https://github.com/mu-editor/mu/actions/runs/7504275586

This job for PR #2487, which uses Python 3.7 to 3.11, and only 3.7 passes:

• https://github.com/mu-editor/mu/actions/runs/7504292209
• https://github.com/mu-editor/mu/actions/runs/7730701490

As the commit was pushed on the 12th of January, something in the runners or the Pyhon action must have changed since then (edit: can replicate locally with a clean installation of Mu in a Python 3.8 virtual env):

• https://github.com/actions/runner-images/issues/
• https://github.com/actions/setup-python/issues

[carlosperate]

Looks like the issue is with a change introduced in pytest v8.0.0 (Python 3.8+), as setting the max pytest version to v7.4.4 works.