Upgrade operator-sdk to 1.28.0

[roypaulin]

Changes reflect migration steps as outlined here:
https://sdk.operatorframework.io/docs/upgrading-sdk-version/v1.28.0/

prior version was v1.25.2

Go version moved to 1.19.6
golanci-lint version moved to 1.51.1

[spilchen]

Just a few comments...

[spilchen]

There is an update missing in tests/external-images-common-ci.txt

[spilchen]

Did we need to make this change?

    [gov4alpha] For scaffolds, replace scaffoldings of v1beta1 by using k8s.io/api/admission/v1 instead of k8s.io/api/admission/v1beta1 as v1beta1 is removed in latest k8s.

  - admissionv1beta1 "k8s.io/api/admission/v1beta1"
  + admissionv1 "k8s.io/api/admission/v1"

https://v1-28-x.sdk.operatorframework.io/docs/upgrading-sdk-version/v1.28.0/

We don't use the gov4 plugin. But is this needed to run the operator on k8s 1.26?

[roypaulin]

Did we need to make this change?

    [gov4alpha] For scaffolds, replace scaffoldings of v1beta1 by using k8s.io/api/admission/v1 instead of k8s.io/api/admission/v1beta1 as v1beta1 is removed in latest k8s.

  - admissionv1beta1 "k8s.io/api/admission/v1beta1"
  + admissionv1 "k8s.io/api/admission/v1"

https://v1-28-x.sdk.operatorframework.io/docs/upgrading-sdk-version/v1.28.0/

We don't use the gov4 plugin. But is this needed to run the operator on k8s 1.26?

Yes I read some doc on this and k8s.io/api/admission/v1beta1 has been deprecated for a while (since v1.19). Maybe we should just upgrade to v1? Any reason to stick to v1beta1?

[spilchen]

No reason to stick with v1beta1. The minimum k8s version we officially support is 1.21.1+. So, lets change it.