Update unsecured gRPC call troubleshooting (#20196)

Author: JamesNK

aspnetcore/grpc/troubleshoot.md

@@ -70,7 +70,7 @@ var client = new Greet.GreeterClient(channel);
 
 ## Call insecure gRPC services with .NET Core client
 
-Additional configuration is required to call insecure gRPC services with the .NET Core client. The gRPC client must set the `System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport` switch to `true` and use `http` in the server address:
+When an app is using .NET Core 3.x, additional configuration is required to call insecure gRPC services with the .NET Core client. The gRPC client must set the `System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport` switch to `true` and use `http` in the server address:
 
 ```csharp
 // This switch must be set before creating the GrpcChannel/HttpClient.
@@ -82,6 +82,8 @@ var channel = GrpcChannel.ForAddress("http://localhost:5000");
 var client = new Greet.GreeterClient(channel);
 ```
 
+.NET 5 apps don't need additional configuration, but to call insecure gRPC services they must use `Grpc.Net.Client` version 2.32.0 or later.
+
 ## Unable to start ASP.NET Core gRPC app on macOS
 
 Kestrel doesn't support HTTP/2 with TLS on macOS and older Windows versions such as Windows 7. The ASP.NET Core gRPC template and samples use TLS by default. You'll see the following error message when you attempt to start the gRPC server: