Update python versions metadata

Author: ojarva

setup.py

@@ -23,10 +23,11 @@
         'Topic :: Security',
         'License :: OSI Approved :: BSD License',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: Implementation :: PyPy',
     ],
     keywords='ssh pubkey public key openssh ssh-rsa ssh-dss ssh-ed25519',