Update ubuntu version for backport action (#6809) (#6810)

Co-authored-by: Steve Gordon <sgordon@hotmail.co.uk>

Author: github-actions[bot]

.github/workflows/backport.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   backport:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-22.04
     name: Backport
     steps:
       - name: Backport