Update ubuntu image to 22.04 (#12495)

Author: davidwengier

azure-pipelines.yml

@@ -240,7 +240,7 @@ stages:
           options: --init # This ensures all the stray defunct processes are reaped.
         pool:
           name: NetCore-Public
-          demands: ImageOverride -equals Build.Ubuntu.2004.Amd64.Open
+          demands: ImageOverride -equals Build.Ubuntu.2204.Amd64.Open
 
         strategy:
           matrix: