chore: Apply OGX license header to multi-SDK OpenAPI generator.

Signed-off-by: Sébastien Han <seb@redhat.com>

Author: leseb

scripts/openapi_generator/multi_sdk.py

@@ -1,3 +1,9 @@
+# Copyright (c) The OGX Contributors.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 # All rights reserved.
 #