Adjust columns for kubectl gs get releases

[njuettner]

What does this PR do?

Towards: giantswarm/roadmap#3721

Before:

VERSION                 STATUS   AGE   KUBERNETES   CONTAINER LINUX   COREDNS   CALICO
cloud-director-27.0.0   ACTIVE   44h   1.27.16      n/a                         n/a

After:

VERSION                 STATUS   AGE   KUBERNETES   FLATCAR    CILIUM   COREDNS   OBSERVABILITY BUNDLE   SECURITY BUNDLE
cloud-director-27.0.0   ACTIVE   44h   1.27.16      3815.2.5   0.25.1   1.21.0    1.5.3                  1.8.0

[marians]

This looks good. Just one question: why the renaming of the column from "Container Linux" to "Flatcar"? As far as I can see on https://www.flatcar.org/ it's still called Flatcar Container Linux.

[AverageMarcus]

I don't think we never refer to it as "container linux", at least not that I've seen. We always say "Flatcar" in our releases and when talking to customers so it should help with consistency.

[marians]

All right

[Gacko]

Out of curiosity, maybe there's an UX reason for it: Why don't we use the CRD native possibility of displaying fields in just a normal kubectl get? As far as I can tell we're already doing this for some.