update licensing info

tests/conftest.py

@@ -1,5 +1,5 @@
 # SPDX-FileCopyrightText: 2026 Filmhuis Den Haag
-# SPDX-License-Identifier:
+# SPDX-License-Identifier: AGPL-3.0-or-later
 
 import asyncio
 from collections.abc import AsyncGenerator, Iterator