Specifying office feed.

Author: mijpeterson

.github/workflows/pr-azure-pipelines.yml

@@ -75,7 +75,7 @@ extends:
             inputs:
               command: restore
               feedsToUse: select
-              vstsFeed: $(VSTS_FEED_ID)
+              vstsFeed: Office
               includeNuGetOrg: false
           # 1ES PT requires explicit build task for Roslyn analysis. Auto-injected Roslyn task will use build logs from this build.
           - task: DotNetCoreCLI@2