Release cluster-api plugin to ArtifactHub

[rafael-azevedo]

The cluster-api plugin was merged in #273 but hasn't been released to ArtifactHub yet. Other plugins (flux, keda, knative, radius, etc.) have artifacthub-pkg.yml and GitHub releases, but cluster-api is missing both.

I'm working on integrating Headlamp with the CAPI plugin into the Cluster API Tilt dev environment (kubernetes-sigs/cluster-api#13516) and would need this published to make the auto-install work.

Built it from source and confirmed it works just needs the release pipeline run. Happy to help with a PR adding the artifacthub-pkg.yml if that's useful.

[illume]

Hello. We plan to do a first release 'soon'. Probably within the next week.