Update python versions

Author: ojarva

.github/workflows/python-tests.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
+        python-version: ["3.9", "3.10", "3.11"]
 
     steps:
     - uses: actions/checkout@v2

setup.py

@@ -23,11 +23,9 @@
         'Topic :: Security',
         'License :: OSI Approved :: BSD License',
         'Programming Language :: Python :: 3',
-        '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 :: 3.11',
         'Programming Language :: Python :: Implementation :: PyPy',
     ],
     keywords='ssh pubkey public key openssh ssh-rsa ssh-dss ssh-ed25519',