Fix link in create digital twins section (Azure#20305)

Previous link had a reference to old pull request.

Author: TechnicallyWilliams

sdk/digitaltwins/Azure.DigitalTwins.Core/samples/Readme.md

@@ -138,7 +138,7 @@ catch (Exception ex)
 
 ### Create digital twins
 
-For Creating Twin you will need to provide Id of a digital Twin such as `myTwin` and the application/json digital twin based on the model created earlier. You can look at sample application/json [here](https://github.com/Azure/azure-sdk-for-net-pr/tree/feature/IoT-ADT/sdk/digitaltwins/Azure.DigitalTwins.Core/samples/DigitalTwinsClientSample/DTDL/DigitalTwins "DigitalTwin").
+For Creating Twin you will need to provide Id of a digital Twin such as `myTwin` and the application/json digital twin based on the model created earlier. You can look at sample application/json [here](https://github.com/Azure/azure-sdk-for-net/blob/master/sdk/digitaltwins/Azure.DigitalTwins.Core/samples/DigitalTwinsClientSample/DTDL/DigitalTwins "DigitalTwin").
 
 One option is to use the provided class BasicDigitalTwin for serialization and deserialization.
 It uses functionality from the `System.Text.Json` library to maintain any unmapped json properties to a dictionary.