Merge the ARM Docker images into the existing images (multi-platform images)

[mnapoli]

See brefphp/bref#1043 (comment) and the discussion.

[mnapoli]

This is more complex than I anticipated. Currently blocked on this: docker/buildx#59 (comment)

What this issue means is that it's impossible/hard to build multi-platform images locally, then run tests/export layers, then push to Docker Hub. Currently multi-platform images MUST be pushed immediately to Docker Hub.

I will revert to separate images for the Bref v2.0 release, and will later work on unifying them.

[shouze]

@mnapoli you also have the option to use docker manifest create.

An example: https://stackoverflow.com/a/70306574

So the idea would be to keep building separately tagged images (eg php-82-x86, php-82-arm64). Then triggering a manifest create workflow dispatch at the end of any build workflow of a given arch.

The manifest create workflow should be able to gently fail depending of the builds race condition. But when it is triggered at the time you have all archs images built & tagged, then you're ready to merge then thanks to docker manifest create command and then push them.

Final note: in fact when you trigger the manifest create github action workflow, best option is to pass docker image couple of unique hashs, not named tags.