fix: Add setup.py for Python 3.6 pip compat (editable installs)

Author: dvershinin

setup.py

@@ -0,0 +1,9 @@
+#!/usr/bin/env python
+"""Setup script for backwards compatibility with Python 3.6 pip."""
+
+from setuptools import setup
+
+# All configuration is in pyproject.toml
+# This file exists for compatibility with older pip versions
+# that don't support PEP 660 (editable installs from pyproject.toml)
+setup()