Add copyright and licensing information

tests/integration_tests/test_scheduling_marking.py

@@ -1,3 +1,9 @@
+# Copyright The PFDL Contributors
+#
+# Licensed under the MIT License.
+# For details on the licensing terms, see the LICENSE file.
+# SPDX-License-Identifier: MIT
+
 """Contains integration tests to check the marking of the petri net."""
 
 # standard libraries