Remove 3.9 classifier as it still isn't recognized

Author: mbeacom

setup.py

@@ -140,7 +140,6 @@ def run(self):
         "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
-        "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3 :: Only",
         "Programming Language :: Python :: Implementation :: CPython",
         "Topic :: Internet",