add better link for gcp auth plugin doc

Kubernetes-commit: 6a8579d1cd3ddeea6c012a4c0fdb7e32687a83f1

Author: mikedanese

plugin/pkg/client/auth/gcp/gcp.go

@@ -116,11 +116,9 @@ type gcpAuthProvider struct {
 var warnOnce sync.Once
 
 func newGCPAuthProvider(_ string, gcpConfig map[string]string, persister restclient.AuthProviderConfigPersister) (restclient.AuthProvider, error) {
-	// deprecated in v1.22, remove in v1.25
-	// this should be updated to use klog.Warningf in v1.24 to more actively warn consumers
 	warnOnce.Do(func() {
-		klog.V(1).Infof(`WARNING: the gcp auth plugin is deprecated in v1.22+, unavailable in v1.25+; use gcloud instead.
-To learn more, consult https://kubernetes.io/docs/reference/access-authn-authz/authentication/#client-go-credential-plugins`)
+		klog.Warningf(`WARNING: the gcp auth plugin is deprecated in v1.22+, unavailable in v1.25+; use gcloud instead.
+To learn more, consult https://cloud.google.com/blog/products/containers-kubernetes/kubectl-auth-changes-in-gke`)
 	})
 
 	ts, err := tokenSource(isCmdTokenSource(gcpConfig), gcpConfig)