kubeconfig cluster.proxy-url is being ignored by kube client

[gustavobini]

I was checking the remote cluster API with a target private cluster in GKE. I had setup a service proxy to connect from the flux cluster to the remote cluster, but it does not work as the cluster.proxy-url field in kubeconfig is being ignored by Flux.

I confirmed it by checking the https://github.com/fluxcd/pkg/blob/main/runtime/client/kubeconfig.go#L70 code.

Would it be possible to use proxy-url? I understand it might not be a small change since it's on the pkgs.