Add python-3.9 Trove classifier

Signed-off-by: Robbie Harwood <[email protected]>

Author: frozencemetery

setup.py

@@ -336,6 +336,7 @@ def gssapi_modules(lst):
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: ISC License (ISCL)',
         'Programming Language :: Python :: Implementation :: CPython',