Replace k8s.gcr.io with registry.k8s.io

[xmudrii]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

This PR replaces all k8s.gcr.io references with registry.k8s.io. See the linked issue for more details.

Which issue(s) this PR fixes:
xref kubernetes/k8s.io#4738

Release note:

Replace all `k8s.gcr.io` references with `registry.k8s.io`

[coveralls]

Coverage: 83.952%. Remained the same when pulling 0d2f3b1 on xmudrii:registry-k8s-io into 58fa16b on kubernetes-sigs:master.

[ambiknai]

Hi @xmudrii
Does the image get automatically pushed to registry.k8s.io hence forth when we create a release tag or should we raise PR for that in k8s.io repository

[xmudrii]

@ambiknai If you already push to k8s.gcr.io, then your images will be available under registry.k8s.io automatically. You can find more details about how registry.k8s.io works in the project repo.

[ambiknai]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ambiknai, xmudrii

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