Update ubuntu version in azure pipeline (#260)

Updated the Azure DevOps pipeline configuration to use ubuntu-24.04 as the virtual machine image instead of ubuntu-20.04.

Author: vvolam

azure-pipelines.yml

@@ -24,7 +24,7 @@ stages:
       DIFF_COVER_CHECK_THRESHOLD: 80
       DIFF_COVER_ENABLE: 'true'
     pool:
-      vmImage: ubuntu-20.04
+      vmImage: ubuntu-24.04
 
     container:
       image: sonicdev-microsoft.azurecr.io:443/sonic-slave-bookworm:$(BUILD_BRANCH)