Update ml-agents/setup.py

Co-authored-by: Chris Elion <chris.elion@unity3d.com>

ml-agents/setup.py

         ]
     },
     cmdclass={"verify": VerifyVersionCommand},
-    extras_require={"torch": ["torch==1.5.0"]},
+    extras_require={"torch": ["torch>=1.5.0"]},
 )