Fix CI

[jmsche]

• Fix code style after new release of PHP CS Fixer
• Update runs-on Ubuntu version used in GitHub Actions

[jmsche]

I don't know why Tests are cancelled by GitHub :/

[jmsche]

Okay, that's why: https://github.com/actions/runner-images/issues/6002

I'll update the OS as well in this PR & change the title.

[weaverryan]

Thanks @jmsche!