Use new releases for CAPA cluster templates

[nprokopic]

What does this PR do?

Towards giantswarm/roadmap#3466

• CAPA only change for new releases: render release version in config instead of cluster-aws version in App resource.

What is the effect of this change to users?

Users must specify --release flag when rendering templates for new CAPA clusters.

What does it look like?

See --release flag and .global.release.version config set, while App .spec.version is not set.

kubectl gs template cluster --provider capa --name nikola --organization giantswarm --release 25.0.0
---
apiVersion: v1
data:
  values: |
    global:
      connectivity:
        availabilityZoneUsageLimit: 3
        network: {}
        topology: {}
      controlPlane: {}
      metadata:
        name: nikola
        organization: giantswarm
        preventDeletion: false
      nodePools:
        nodepool0:
          instanceType: m5.xlarge
          maxSize: 10
          minSize: 3
          rootVolumeSizeGB: 8
      providerSpecific: {}
      release:
        version: 25.0.0
kind: ConfigMap
metadata:
  creationTimestamp: null
  labels:
    giantswarm.io/cluster: nikola
  name: nikola-userconfig
  namespace: org-giantswarm
---
apiVersion: application.giantswarm.io/v1alpha1
kind: App
metadata:
  labels:
    app-operator.giantswarm.io/version: 0.0.0
  name: nikola
  namespace: org-giantswarm
spec:
  catalog: cluster
  config:
    configMap:
      name: ""
      namespace: ""
    secret:
      name: ""
      namespace: ""
  kubeConfig:
    context:
      name: ""
    inCluster: true
    secret:
      name: ""
      namespace: ""
  name: cluster-aws
  namespace: org-giantswarm
  userConfig:
    configMap:
      name: nikola-userconfig
      namespace: org-giantswarm
  version: ""

Any background context you can provide?

• Implement Releases RFC roadmap#3466
• Releases implementation rfc#96

What is needed from the reviewers?

Check if I missed to change something.

Do the docs need to be updated?

I don't think so.

Should this change be mentioned in the release notes?

• CHANGELOG.md has been updated

Is this a breaking change?

Maybe, as --release flag is needed for CAPA clusters now, but's a change for CAPA clusters, and I don't think it's a change for kubectl-gs.

[nprokopic]

Will fix the tests.