chore: Add SPDX header

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

.devcontainer/setup.sh

@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# SPDX-FileCopyrightText: 2023 Nextcloud GmbH and Nextcloud contributors
+# SPDX-License-Identifier: CC0-1.0
+
 (
     cd /tmp && /usr/local/bin/bootstrap.sh apache2ctl start
 )