Update default sample to match latest API changes

Author: rido-min

articles/iot-develop/concepts-model-repository.md

@@ -50,8 +50,8 @@ The client accepts a `DTMI` as input and returns a dictionary with all required
 using Azure.IoT.ModelsRepository;
 
 var client = new ModelsRepositoryClient();
-IDictionary<string, string> models = client.GetModels("dtmi:com:example:TemperatureController;1");
-models.Keys.ToList().ForEach(k => Console.WriteLine(k));
+ModelResult models = client.GetModel("dtmi:com:example:TemperatureController;1");
+models.Content.Keys.ToList().ForEach(k => Console.WriteLine(k));
 ```
 
 The expected output should display the `DTMI` of the three interfaces found in the dependency chain: