Add python-requires in setup.py (#8989)

* Add python-requires in setup.py

* Update setup.py
diff --git a/python/setup.py b/python/setup.py
index f639732..50fd5be 100755
--- a/python/setup.py
+++ b/python/setup.py
@@ -308,4 +308,5 @@
       },
       install_requires=install_requires,
       ext_modules=ext_module_list,
+      python_requires='>=3.5',
   )