Add dotnet.config

Author: Youssef1313

test/dotnet-new.IntegrationTests/DotnetNewTestTemplatesTests.cs

@@ -193,6 +193,14 @@ public void MSTestAndPlaywrightProjectTemplate_WithCoverageToolAndTestRunner_Can
 
             if (runDotnetTest)
             {
+                if (testRunner == "Microsoft.Testing.Platform")
+                {
+                    File.WriteAllText(Path.Combine(outputDirectory, "dotnet.config"), """
+                        [dotnet.test.runner]
+                        name = "Microsoft.Testing.Platform"
+                        """);
+                }
+
                 var result = new DotnetTestCommand(_log, false)
                 .WithWorkingDirectory(outputDirectory)
                 .Execute(outputDirectory);