Use bookworm-tagged slave container for now

Signed-off-by: Saikrishna Arcot <[email protected]>

Author: saiarcot895

.azure-pipelines/build-template.yml

@@ -39,7 +39,7 @@ jobs:
   timeoutInMinutes: ${{ parameters.timeout }}
 
   container:
-    image: sonicdev-microsoft.azurecr.io:443/${{ parameters.sonic_slave }}:latest
+    image: sonicdev-microsoft.azurecr.io:443/${{ parameters.sonic_slave }}:bookworm
 
   steps:
   - checkout: self