Pin more-itertools for 3.9 compatibility

Author: Cole-Greer

gremlin-console/src/test/python/setup.py

@@ -32,6 +32,7 @@
     tests_require=[
         'pytest>=4.6.4,<5.0.0',
         'mock>=3.0.5,<4.0.0',
+        'more-itertools<11.0.0',
         'pexpect==4.8.0'
     ]
 )