fix(Reuse): add license info to rector.php

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

Author: blizzz

rector.php

@@ -2,6 +2,11 @@
 
 declare(strict_types=1);
 
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
 use Nextcloud\Rector\Set\NextcloudSets;
 use Rector\Config\RectorConfig;