Prototype using Gihtub Container Registry for KIC Base Builds instead of GCR

[medyagh]

while reviewing the PR to bump the flannel, I noticed they moved to github resgistry to host their images https://github.com/flannel-io/flannel/pull/2177/files
Last time I tried Github Container Registry the users had to be logged in to Git to be able to pull images ...but I I think it i no longer the case ...
anyone knows about that ?
I was able to pull an image on github without being authenticted to github

(inside minikube VM)
$ docker pull ghcr.io/flannel-io/flannel-cni-plugin:v1.6.2-flannel1
v1.6.2-flannel1: Pulling from flannel-io/flannel-cni-plugin
b2e6f696af52: Pull complete 
98aab8cf7a8a: Pull complete 
Digest: sha256:f1812994f0edbcb5bb5ccb63be2147ba6ad10e1faaa7ca9fcdad4f441739d84f
Status: Downloaded newer image for ghcr.io/flannel-io/flannel-cni-plugin:v1.6.2-flannel1
ghcr.io/flannel-io/flannel-cni-plugin:v1.6.2-flannel1

I am thinking we should experiment with pushing images to github instead of GCR for Images that pushed to the PR

/Users/medya/workspace/minikube/hack/jenkins/kicbase_auto_build.sh