Allow cross architecture docker builds with docker buildx

[kushal-ti]

Is your feature request related to a problem? Please describe

I want to be able to build docker images with leeway that can target ARM64 cpus, without needing to switch to an ARM machine in development

Describe the behaviour you'd like

An option to specify target architecture for docker which can make use of the docker buildx extension. Leeway already allows specifying GOARCH to compile go binaries for ARM64 targets, a similar feature for docker builds would also be extremely helpful

Describe alternatives you've considered

Running the entire build on an ARM machine. I would assume that this would lead to the build automatically being created for an ARM target
However, this would require both devs and CI pipelines to switch/add a new machine to their workflows to build for ARM

[axonasif]

Hi @kushal-ti, is this related with Gitpod self-hosted?

[kushal-ti]

Yes, it is

[axonasif]

This is not doable right now.