Enable pushing to the main-ub VMR branch (#18411)

eng/pipelines/templates/jobs/vmr-synchronization.yml

@@ -23,7 +23,7 @@ parameters:
 
 jobs:
 - job: ${{ parameters.jobName }}
-  displayName: Synchronize dotnet/dotnet
+  displayName: Synchronize VMR's ${{ parameters.vmrBranch }}
   timeoutInMinutes: 120
   variables:
   - template: /eng/common/templates/variables/pool-providers.yml
@@ -40,7 +40,7 @@ jobs:
       - group: DotNetBot-AzDO-PAT
       - name: vmrInternalUrl
         value: https://dnceng@dev.azure.com/dnceng/internal/_git/dotnet-dotnet
-  
+
   pool:
     ${{ if eq(variables['System.TeamProject'], 'public') }}:
       name: $(DncEngPublicBuildPool)
@@ -63,7 +63,7 @@ jobs:
 
   - ${{ if and(not(parameters.noPush), not(in(variables['Build.Reason'], 'PullRequest')), eq(variables['System.TeamProject'], 'internal')) }}:
     # Push main and release branches to the public VMR
-    - ${{ if or(eq(parameters.vmrBranch, 'main'), startsWith(parameters.vmrBranch, 'release/')) }}:
+    - ${{ if or(eq(parameters.vmrBranch, 'main'), eq(parameters.vmrBranch, 'main-ub'), startsWith(parameters.vmrBranch, 'release/')) }}:
       - script: >
           ./.dotnet/dotnet darc vmr push
           --vmr '$(vmrPath)'