multi-arch oci release github actions example

[dr-housemd]

Much like Docker docs leverage Actions artifacts/cache, we should have a similar example using buildsafe.
In the example , we should:

• leverage github runners of different arch(not use QEMU)
• push image with "bsf oci --push " (we should have a flag --digest that can print out the digest to be saved on disk)
• Merge section of the action can remain as-is since we'll essentially only replace Docker for build in this workflow.

https://docs.docker.com/build/ci/github-actions/multi-platform/#distribute-build-across-multiple-runners

related to broader- #24

[dr-housemd]

we have https://github.com/buildsafedev/multiarch-build-action