Merge pull request #6912 from ryanbrandenburg/UbuntuImage

Update Ubuntu image

azure-pipelines.yml

@@ -363,7 +363,7 @@ stages:
           options: --init # This ensures all the stray defunct processes are reaped.
         pool:
           ${{ if eq(variables['System.TeamProject'], 'public') }}:
-            vmImage: ubuntu-18.04
+            vmImage: ubuntu-latest
           ${{ if eq(variables['System.TeamProject'], 'internal') }}:
             name: NetCore1ESPool-Internal
             demands: ImageOverride -equals Build.Ubuntu.1804.Amd64