Update Python version requirement to 3.11

Author: prandla

docs/Installation.rst

@@ -16,7 +16,7 @@ These are our requirements (in particular we highlight those that are not usuall
 
 * `GNU compiler collection <https://gcc.gnu.org/>`_ (in particular the C compiler ``gcc``);
 
-* `Python <http://www.python.org/>`_ >= 3.9;
+* `Python <http://www.python.org/>`_ >= 3.11;
 
 * `libcg <http://libcg.sourceforge.net/>`_;
 

setup.py

@@ -195,10 +195,11 @@ class build_py_and_l10n(build_py):
     },
     keywords="ioi programming contest grader management system",
     license_expression="AGPL-3.0-only",
+    python_requires=">=3.11",
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Natural Language :: English",
         "Operating System :: POSIX :: Linux",
-        "Programming Language :: Python :: 3.12",
+        "Programming Language :: Python :: 3.11",
     ],
 )