Pull git-sync image from registry.k8s.io

[mhamzahkhan]

Hello,

This is just a PR to change the git-sync registry from k8s.gcr.io to registry.k8s.io as per: https://kubernetes.io/blog/2023/02/06/k8s-gcr-io-freeze-announcement/

[atjones0011]

My team is working on removing all k8s.gcr.io references from our environment and discovered this registry reference today. @slok this PR appears to cover all of the renaming needed. Is the PR able to be merged in?

[coheigea]

Even better if we could bump to registry.k8s.io/git-sync/git-sync:v3.6.7+ which fixes a ton of CVEs in the base image

[mhamzahkhan]

I have updated the PR to use git-sync v3.6.7