Add multi-arch docker-build

[rhnvrm]

Closes #314

[dereulenspiegel]

Any chance that this gets merged soon? Would really love to run beehive on a Raspberry Pi :)

[muesli]

Afraid that's only part of a solution. Ideally we integrate Docker builds with goreleaser, as this release script is a bit obsolete. Sadly there are still issues with goreleaser and cross-platform builds.

We'll also have to disable the automated Docker hub builds, otherwise these approaches will constantly race each other, at least for the latest tag.

I will do a manual build & push for the latest stable release, so you can at least start using it on a Pi.

[muesli]

Actually this is even more complicated than anticipated, because buildx is still an experimental feature and not enabled by default.

[muesli]

This might help us: https://goreleaser.com/customization/docker_manifest/

[rhnvrm]

Hey @muesli

I implemented the github action (ref: #314 (comment)).

This might help us: https://goreleaser.com/customization/docker_manifest/

It uses the same experimental setup, so even if we use goreleaser, you will have to set up buildx locally. To avoid this local setup, we can continue using goreleaser to create the tag and push it to the repo; on push of the tag, the github action will build and push the docker image. (ref this PR: c2aca9d)