kubeadm: mark v1beta2 as deprecated

cmd/kubeadm/app/util/config/common.go

@@ -69,7 +69,9 @@ func validateSupportedVersion(gv schema.GroupVersion, allowDeprecated bool) erro
 	}
 
 	// Deprecated API versions are supported by us, but can only be used for migration.
-	deprecatedAPIVersions := map[string]struct{}{}
+	deprecatedAPIVersions := map[string]struct{}{
+		"kubeadm.k8s.io/v1beta2": {},
+	}
 
 	gvString := gv.String()
 

cmd/kubeadm/app/util/config/common_test.go

@@ -73,6 +73,7 @@ func TestValidateSupportedVersion(t *testing.T) {
 				Group:   KubeadmGroupName,
 				Version: "v1beta2",
 			},
+			allowDeprecated: true,
 		},
 		{
 			gv: schema.GroupVersion{