Update markers of supported Python versions

Signed-off-by: Ivan Kanakarakis <[email protected]>

Author: c00kiemon5ter

setup.py

@@ -38,6 +38,9 @@
         "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",
     ],
     entry_points={
         "console_scripts": ["satosa-saml-metadata=satosa.scripts.satosa_saml_metadata:construct_saml_metadata"]