metropolis: remove stutter in ClusterConfiguration.KubernetesConfig

We already know this is a config (it lives in ClusterConfiguration), no
need to call that a config again.

This doesn't break any compatibility yet as field names are not (yet)
under a stability guarantee.

Change-Id: Ib6492d1c8303cbd0620b979b8047ec9757e301c0
Reviewed-on: https://review.monogon.dev/c/monogon/+/3594
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/test/launch/cli/launch-cluster/main.go b/metropolis/test/launch/cli/launch-cluster/main.go
index 793cc28..f5e0537 100644
--- a/metropolis/test/launch/cli/launch-cluster/main.go
+++ b/metropolis/test/launch/cli/launch-cluster/main.go
@@ -135,8 +135,8 @@
 
 func main() {
 	clusterConfig := cpb.ClusterConfiguration{
-		KubernetesConfig: &cpb.ClusterConfiguration_KubernetesConfig{
-			NodeLabelsToSynchronize: []*cpb.ClusterConfiguration_KubernetesConfig_NodeLabelsToSynchronize{
+		Kubernetes: &cpb.ClusterConfiguration_Kubernetes{
+			NodeLabelsToSynchronize: []*cpb.ClusterConfiguration_Kubernetes_NodeLabelsToSynchronize{
 				{Regexp: "^" + mlaunch.NodeNumberKey + "$"},
 			},
 		},