The universally advertized way of building Docker images with GitHub is to set up a GitHub Actions workflow.
Github Actions (GA) is actually very easy to use but nonetheless still under heavy development.
Unfortunately, almost all tutorials out there are based on (the same) very simplistic use cases. I just couldn’t get it right by simply following them : I’ve literally spent hours to test and understand how to leverage the cache action for Docker multi-stage builds.
I hope this post will be useful to anyone with a similar use case.