docker-build-and-push should not push an image for every commit to main

[xmfcx]

Before this PR, docker-build-and-push was being triggered only on schedule.

After this change, and still, this action is running and pushing (There are almost daily images published.) per PR.

Was this expected behavior? Do we want the images to be updated this often?

@oguzkaganozt @youtalk

Originally posted by @xmfcx in #4072 (comment)

Resolution

The commits to main should not trigger the this push image action.

Not every change in main branch justifies creation of a new image. (e.g. documentation changes, unrelated CI changes).

And most of the relevant changes happen in the Autoware Universe repo anyways.

If we need to push a new image (and cannot wait for 1st or 15th day of the month), the tag system can be used.

Being solved by:

• ci(docker-build-and-push-main): don't push to registry on commit to main #4888