ci: Update to Ubuntu 24.04 for building the image

Author: sdroege

.github/workflows/image.yml

@@ -16,7 +16,7 @@ on:
 
 jobs:
   docker:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     steps:
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v3