Update actions/checkout from v4 to v5 in all workflows

[Hopium21]

I noticed that all workflow files are still using the outdated actions/checkout v4.
I recommend upgrading to v5 - here’s the link to the latest release: https://github.com/actions/checkout/releases/tag/v5.0.0

If needed, I can replace all instances across your workflows.
Everything was tested locally and works correctly.