ci: bump Python to 3.13

Author: bastimeyer

.github/workflows/main.yml

@@ -21,7 +21,7 @@ jobs:
       - name: Set up python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.12"
+          python-version: "3.13"
 
       - name: Get cpython
         shell: bash