ci: bump Python to 3.12

Author: bastimeyer

.github/workflows/main.yml

@@ -31,7 +31,7 @@ jobs:
       - name: Set up python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.11"
+          python-version: "3.12"
 
       - name: Get cpython
         shell: bash