Update to a buildtools that doesn't reference myget (#28127)

Author: mmitche

BuildToolsVersion.txt

@@ -1 +1 @@
-2.1.0-rc1-05604-03
+2.1.0-rc1-06014-01

dependencies.props

@@ -51,7 +51,7 @@
   <!-- Package versions used as toolsets -->
   <PropertyGroup>
     <FeedTasksPackage>Microsoft.DotNet.Build.Tasks.Feed</FeedTasksPackage>
-    <FeedTasksPackageVersion>2.1.0-rc1-05604-03</FeedTasksPackageVersion>
+    <FeedTasksPackageVersion>2.1.0-rc1-06014-01</FeedTasksPackageVersion>
   </PropertyGroup>
 
   <!-- Publish symbol build task package -->

tests/src/NuGet.Config

@@ -6,7 +6,7 @@
   <packageSources>
     <clear/>
     <add key="myget.org dotnet-core" value="https://dotnetmygetlegacy.blob.core.windows.net/dotnet-core/index.json" />
-    <add key="myget.org nugetbuild" value="https://www.myget.org/F/nugetbuild/api/v3/index.json" />
+    <add key="nuget-build" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/nuget-build/nuget/v3/index.json" />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
   </packageSources>
   <activePackageSource>