Tribute to deprecated components: add license information to files for matrix-sliding-sync

This commit adds copyright attirbutions in SPDX format to files for matrix-sliding-sync, following the REUSE's specification.

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

roles/custom/matrix-sliding-sync/tasks/install.yml

@@ -1,3 +1,8 @@
+# SPDX-FileCopyrightText: 2023 - 2024 Slavi Pantaleev
+# SPDX-FileCopyrightText: 2024 David Mehren
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
 ---
 
 - name: Ensure matrix-sliding-sync paths exist

roles/custom/matrix-sliding-sync/tasks/main.yml

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2023 Slavi Pantaleev
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
 ---
 
 - tags:

roles/custom/matrix-sliding-sync/tasks/uninstall.yml

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2023 Slavi Pantaleev
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
 ---
 
 - name: Check existence of matrix-sliding-sync service

roles/custom/matrix-sliding-sync/tasks/validate_config.yml

@@ -1,3 +1,8 @@
+# SPDX-FileCopyrightText: 2023 - 2024 Slavi Pantaleev
+# SPDX-FileCopyrightText: 2024 MDAD project contributors
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
 ---
 - name: Fail if required matrix-sliding-sync settings not defined
   ansible.builtin.fail: