GitHub Action improvements

[FlyGoat]

• Bump all action versions to avoid warnings.
• CI & docker image build now run on all push / pull_request, however images and docs are only published when pushing to main.
• latest tag is applied to any push to main branch.
• Publish image to both ghcr and docker.io.

See: https://github.com/FlyGoat/subsai/actions/runs/11630804678 https://github.com/FlyGoat/subsai/actions/runs/11630804691 https://github.com/FlyGoat/subsai/pkgs/container/subsai

For a demo run on main branch.

[abdeladim-s]

Sounds Great! Thanks a lot @FlyGoat for the contribution!