Add pyproject.toml to enable pip install

Signed-off-by: Rob Elliott <Robert.Elliott@arm.com>
Change-Id: Ib052470d183db5a54a4cd26fc5df42e4c1bc5341
diff --git a/setup.py b/setup.py
new file mode 100644
index 0000000..3008a9e
--- /dev/null
+++ b/setup.py
@@ -0,0 +1,18 @@
+# Copyright (c) 2023, ARM Limited.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+
+"""Setup script for backward compatibility."""
+from setuptools import setup
+
+setup()