File msbuild-16.6-update-dotnet-feed.patch of Package msbuild

diff -uNr a/NuGet.config b/NuGet.config
--- a/NuGet.config	2021-01-16 06:11:13.000000000 +0900
+++ b/NuGet.config	2025-07-30 23:13:42.000000000 +0900
@@ -2,7 +2,8 @@
 <configuration>
   <packageSources>
     <clear />
-    <add key="dotnet-core" value="https://dotnetfeed.blob.core.windows.net/dotnet-core/index.json" />
+    <add key="dotnet3.1" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet3.1/nuget/v3/index.json" />
+    <add key="dotnet3.1-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet3.1-transport/nuget/v3/index.json" />
     <add key="arcade" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-eng/nuget/v3/index.json" />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
     <add key="dotnet-tools" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nuget/v3/index.json" />