Support ARMv8 on DockerHub

[GGORG0]

I was just trying to run a server on my Raspberry Pi 4 (64bit OS).
I'm getting this error:

The requested image's platform (linux/amd64) does not match the detected host platform (linux/arm64/v8) and no specific platform was requested

I'm not really into Docker development, but from what I remember you need to build and publish the ARM image on the hub (and the easiest way to do that if you don't have an ARM machine is GitHub Actions).

I'll try to build the image myself, but having an official ARMv8 (and other ARM, like 32bit) build would help others.

As soon as I get the server working I'll open a PR to add it to the public list!