Updated windows build image override

Author: vseanreesermsft

eng/pipelines/windows.yml

@@ -109,10 +109,10 @@ stages:
         pool:
           ${{ if ne(variables['System.TeamProject'], 'public') }}:
             name: NetCore1ESPool-Svc-Internal
-            demands: ImageOverride -equals Build.Windows.10.Amd64.VS2017
+            demands: ImageOverride -equals Windows.10.vs2019.amd64
           ${{ if eq(variables['System.TeamProject'], 'public') }}:
             name: NetCore-Svc-Public
-            demands: ImageOverride -equals Build.Windows.10.Amd64.VS2017.Open
+            demands: ImageOverride -equals Windows.10.vs2019.amd64.Open
 
         submitToHelix: true
         # Temporarily until we increase the Windows ARM64 queue, https://github.com/dotnet/core-eng/issues/7756