use cluster-name as default label everywhere

[FxKu]

and replace code were the label "version" was hard-coded

[Jan-M]

I dont like that this is hard coded. We should have the end to end test covering that the label can change to make sure config variable is picked up.

[FxKu]

Yeah, but there are even more selectors hard coded here: spilo-role, name etc.
But true, I could add a test on changing such labels

[Jan-M]

👍

[FxKu]

👍

[RafiaSabih]

👍

[Bryji]

This was a breaking change for us. The operator was no longer able to update statefulsets as Kubernetes does not allow you to change the label on an existing sts:
time="2020-02-28T18:50:54Z" level=warning msg="error while syncing cluster state: could not sync statefulsets: could not update statefulset: could not patch statefulset spec \"postgres-operator/platops-postgres-operator-platypusdb\": StatefulSet.apps \"platops-postgres-operator-platypusdb\" is invalid: spec: Forbidden: updates to statefulset spec for fields other than 'replicas', 'template', and 'updateStrategy' are forbidden" cluster-name=postgres-operator/platops-postgres-operator-platypusdb pkg=cluster
Fix was to set the cluster_name_label back to "version" in our base values file

  configKubernetes:
    cluster_name_label: "version"

Posting the comment here for any others looking for the root cause/fix.