Force python 3.12 when building ubuntu 24.04 package.

Author: Kasper Peeters

.github/workflows/ubuntu-24.04-package.yml

@@ -19,6 +19,11 @@ jobs:
 #      if: github.ref != 'refs/heads/devel'
 #      run: exit 1
 
+    - name: setup python
+      uses: actions/setup-python@v4
+      with:
+          python-version: 3.12
+
     - name: Set up GitHub CLI
       run: |
         sudo apt-get update