Copying the nuget.config template for the publish web app test, so that the new tools packages can be resolved.

test/dotnet-migrate.Tests/GivenThatIWantToMigrateTestApps.cs

@@ -137,6 +137,8 @@ namespace Microsoft.DotNet.Migration.Tests
 
             var projectDirectory = testInstance.Root.FullName;
             
+            File.Copy("NuGet.tempaspnetpatch.config", Path.Combine(projectDirectory, "NuGet.Config"));
+
             MigrateProject(new [] { projectDirectory });
 
             Restore(projectDirectory);