Use env python

gensetup.py

@@ -49,7 +49,7 @@ def load_version():
 if argv[1] == '--setup.py':
     with open('setup.py', 'wt') as f:
         print(
-f'''#!/usr/bin/python3
+f'''#!/usr/bin/env python3
 # This file is auto generated. Do not modify
 from setuptools import setup