Add Docker labels for ghcr.io

[applejag]

Finally figured out why the pushed images didn't appear on the GitHub page. You have to link them with a Docker label.

[jadolg]

Do you mean here?

Nevermind, I just noticed Earthfile

[applejag]

Yes, I meant there. I pushed the image before and it didn't appear. It was first when I added these labels that you see in the PR changes that the package appeared there

[jadolg]

I'm building images using docker buildkit on GitHub and pushing there and so far they have appeared just fine.
Maybe Earthly does it different 🤷‍♂️

[applejag]

@jadolg Our decision to go with Earthly predates our use of GitHub Actions (this repo wasn't always on github.com). We wanted to find something that was easier to use than Jenkins.

Earthly is basically just the combination of a Dockerfile and a Makefile. It was very easy to define our Earthfiles to both build the image, tag it correctly, and push it to our registry.

Nowadays that we have GH Actions we might want to just get rid of it, as I do like having just a Dockerfile available. Now you HAVE to use Earthly, which is less nice.