Add workflows to publish docker container on release

[soapy1]

follow up to #450

Description

This PR adds 2 new GHA workflows:

• build docker image (on every pull request)
• adds building+publishing docker image to GH container registry as part of the release workflow

Pull request checklist

• Did you test this change locally?
• Did you update the documentation (if required)?
• Did you add/update relevant tests for this change (if required)?

[soapy1]

Are there any docs that should be updated about publishing this new release artifact?

[gabalafou]

I'm not sure I'm the right person to review GitHub workflows. I am not familiar enough with workflow files (nor specific workflows such as uploading Docker images) to be able to spot errors.

But I gave this a careful look and left some questions and comments.

[gabalafou]

What's the difference between tags and labels?

[soapy1]

Labels contain metadata about the image (ref link). Tags denote a version of the image. So like, when you go to pull a docker image the form is docker pull <maybe repo>/<namespace>/<image name>:<tag>. For the demo published conda-store-ui container, that is docker pull ghcr.io/conda-incubator/conda-store-ui:sha256-c8c4ab110fec1d39f91ba86df89811bdd5c93bb92037ffb550a684f63ef15c64

[gabalafou]

Are there any docs that should be updated about publishing this new release artifact?

I noticed that there are manual steps in RELEASE.md in case the GitHub action fails. Should there be manual steps for how to publish the Docker image?

[gabalafou]

On the subject of how this appears in the list of checks, currently this shows up as: "Build Docker image / Build Docker Images 🛠️"

I wonder if we can come up with a better combo. Docker / Build image? Not really sure. I also don't think a redundant title is the worst thing in the world (so long as it looks different enough from the other titles)

[gabalafou]

Thanks @soapy1 for addressing my review comments!

I guess we'll find out in the next release if the docker push job works?

[soapy1]

I guess we'll find out in the next release if the docker push job works?

I tested it out pushing images in the build-docker-image workflow. You can see the build image here https://github.com/conda-incubator/conda-store-ui/pkgs/container/conda-store-ui