feat: multi-arch build for OCI image (#2032)

I was trying to build the image on arm64 but this image was specifically
made for x86_64.

I propose to make the image available for other architectures. As we are
using docker buildx we can use the `TARGETARCH` argument ([Automatic
platform ARGs in the global
scope](https://docs.docker.com/reference/dockerfile/#automatic-platform-args-in-the-global-scope)).
2 files changed