[AT-696, AT-714] Update reusable workflows

[tyrann0us]

Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines
• [ ] Tests for the changes have been added (for bug fixes/features)
• [ ] Docs have been added/updated (for bug fixes/features)

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...) Chore

What is the current behavior? (You can also link to an open issue here) https://inpsyde.atlassian.net/browse/AT-696 https://inpsyde.atlassian.net/browse/AT-714

What is the new behavior (if this is a feature change)?

• https://github.com/inpsyde/reusable-workflows/pull/101 was merged, so we can switch from PHP_MATRIX to a native GitHub Actions matrix which passes to PHP_VERSION
• https://github.com/inpsyde/reusable-workflows/pull/43 was merged, so we can switch from feature/ddev-playwright to the main branch

Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?) No

Other information: The initial scope of the PR was extended, so the branch name doesn't match the purpose anymore.

[tyrann0us]

I am toggling the PR draft status in the hope of getting the checks to run.