Fixes #480: Builds multi-platform image for both amd64 and arm64

[antevis]

At build stage, you pass --platform argument, like so:
--platform linux/amd64,linux/arm64

[saleh-mir]

Hey, I'm a complete Docker novice. Can you tell me exactly which command I should run?

Also, do I need to run each build on its own CPU architecture? Do I need to build the AMD64 version on a machine with that architecture and the ARM version on a different server for it to work?

[antevis]

I build manually on an Apple silicon Mac with Docker Desktop installed:

docker build --platform linux/amd64,linux/arm64 -t <dockerhub_username>/jesse:<version> --push .

docker build is actually an alias for docker buildx build
this builds the multi-platform image and pushes it to Docker hub:
https://hub.docker.com/repository/docker/polyconnect/jesse/tags

Your workflow is likely different, but the basic idea is the same

here's the relevant documentation, where the process is described in details, including what pre-requisites should be met:
https://docs.docker.com/build/building/multi-platform/

[saleh-mir]

Thank you for such detailed and quick response.

[edu-diaz]

@saleh-mir could this change be merged?