Update runners to ubuntu-24.04 from deprecated ubuntu-20.04 label

Author: billnapier

.github/workflows/backport.yml

@@ -9,7 +9,7 @@ permissions: {}
 
 jobs:
   backport:
-    runs-on: ubuntu-20.04
+    runs-on: 'ubuntu-24.04'
     name: Backport
     permissions: 
       contents: write