Use k8s.io/cli-runtime for kubernetes flags

Signed-off-by: Jakob Schrettenbrunner <jakob.schrettenbrunner@telekom.de>

cmd/flux/create_receiver.go

@@ -109,7 +109,7 @@ func createReceiverCmdRun(cmd *cobra.Command, args []string) error {
 	receiver := notificationv1.Receiver{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      name,
-			Namespace: rootArgs.namespace,
+			Namespace: *kubeconfigArgs.Namespace,
 			Labels:    sourceLabels,
 		},
 		Spec: notificationv1.ReceiverSpec{
@@ -130,7 +130,7 @@ func createReceiverCmdRun(cmd *cobra.Command, args []string) error {
 	ctx, cancel := context.WithTimeout(context.Background(), rootArgs.timeout)
 	defer cancel()
 
-	kubeClient, err := utils.KubeClient(rootArgs.kubeconfig, rootArgs.kubecontext)
+	kubeClient, err := utils.KubeClient(kubeconfigArgs)
 	if err != nil {
 		return err
 	}