CI/CD does not produce images for some commits

[Miles-Garnsey]

What happened?

CI/CD runs for documentation commits don't produce images. This leads to errors when you try to reference the k8ssandra-operator kustomizations from downstream kustomizations.

All commits on main must create an image to avoid kustomizations being broken.

Definition of done

All commits (inc. docs commits/whatever) generate an image and kustomizations that can be deployed.

[adejanovski]

Sounds good to me if that avoids confusion.
Maybe we could have docs update build and push an image directly instead of going through the whole CI process?
That can help unclutter our CI queue.