ci.yml: Upgrade GitHub Actions

[cclauss]

• https://github.com/actions/checkout/releases
• https://github.com/actions/setup-python/releases
• https://github.com/actions/upload-artifact/releases
• https://github.com/deadsnakes/action/releases

This could be automated via dependabot or other similar tools.

[mattip]

The PR is failing

[cclauss]

Yes. I think we will need to keep using deadsnakes < v3.0... https://github.com/deadsnakes/action/releases/tag/v3.0.0