Add license header to protocol_version.py

Change-Id: Ie52c6f322ec779af668be557a2b4bad69d569922

Author: gtomassorri

cmk/utils/licensing/protocol_version.py

@@ -1,3 +1,9 @@
+#!/usr/bin/env python3
+# Copyright (C) 2025 Checkmk GmbH - License: GNU General Public License v2
+# This file is part of Checkmk (https://checkmk.com). It is subject to the terms and
+# conditions defined in the file COPYING, which is part of this source code package.
+
+
 from typing import Literal
 
 from cmk.ccc.version import Edition, edition