Update the Azure.Monitor installation command

If not specify the released version, installation of Azure.Monitor will return error:There are no stable versions available.
Update the command by specifying the latest version -v 1.0.0-beta.3

Author: ChenCheng368

articles/communication-services/quickstarts/includes/telemetry-app-insights-net.md

@@ -48,7 +48,7 @@ dotnet add package Azure.Communication.Identity --version 1.0.0
 You will also need to install the Azure Monitor Exporter for OpenTelemetry library.
 
 ```console
-dotnet add package Azure.Monitor.OpenTelemetry.Exporter
+dotnet add package Azure.Monitor.OpenTelemetry.Exporter -v 1.0.0-beta.3
 ```
 
 ### Set up the app framework
@@ -159,4 +159,4 @@ Run the application from your application directory with the `dotnet run` comman
 
 ```console
 dotnet run
-```
+```