Improve the showcase app link to point into the correct subfolder

Author: FlorianBorn71

articles/remote-rendering/samples/showcase-app.md

@@ -15,7 +15,7 @@ The Unity showcase application is a Unity-based sample application to demonstrat
 
 ## Source repository
 
-The source code for this application alongside with build/deployment instructions can be found in the [ARR samples repository](https://github.com/Azure/azure-remote-rendering).
+The source code for this application alongside with build/deployment instructions can be found in the [ARR samples repository](https://github.com/Azure/azure-remote-rendering/tree/master/Unity/AzureRemoteRenderingShowcase).
 
 ## Next steps