Add addional legacy feed

Author: dseefeld

repos/Directory.Build.targets

@@ -174,6 +174,9 @@
       <LegacyFeedMapping
         Include="https://dotnet.myget.org/F/dotnet-buildtools/api/v3/index.json"
         NewFeed="https://pkgs.dev.azure.com/dnceng/public/_packaging/myget-legacy/nuget/v3/index.json" />
+      <LegacyFeedMapping
+        Include="https://dotnet.myget.org/F/nuget-volatile/api/v3/index.json"
+        NewFeed="https://pkgs.dev.azure.com/dnceng/public/_packaging/myget-legacy/nuget/v3/index.json" />
     </ItemGroup>
 
     <ReplaceFeedsInNugetConfig InputFile="%(NuGetConfigFiles.Identity)"