Migrate from Prow staging to registry.k8s.io

[tuminoid]

We're using gcr.io based Prow images in project-infra. k8s stopped publishing images 2 months ago, hence we're not getting autobumper to bump new images anymore.

Ref: #869 (comment)

[tuminoid]

/kind bug
/triage accepted

[tuminoid]

It should be noted that Prow images do not have published production images available yet. Migration to registry.k8s.io is not done yet, and they look for volunteers to help.

[tuminoid]

#908 makes us use the staging registry as intemediate measure, as we haven't had any Prow image updates for 3 months now. There is activity in #prow community to complete the migration, but we can move to that when its done. We need some fixes from Prow sooner than that happens.

[tuminoid]

/lifecycle frozen

Freezing this for now as it is waiting external actions.

[tuminoid]

Updated title as per #871 (comment) we have moved to using Prow staging images, so the task is no longer to move from deprecated location, but from "unofficial" location. Community is still working in migration, so we'll wait.