Xcode StoreKit Configuration with Simulator: Refund and deleting transactions is not supported

[Mike Chong]

1. Add a StoreKit configuration file to the Example project. like:
   
2. Test the store kit purchase and refund (or delete)

(You can git clone https://github.com/imWildCat/merchantkit-forked-example to test. Basically, this fork does not change anything except adding the StoreKit configuration file)

Actual behavior

After refund or deleting, the state is still purchased

480.mk.mov

Expected behavior

After refund or deleting, the state is still purchasable, compared with Apple's sample code: https://developer.apple.com/documentation/swiftui/fruta_building_a_feature-rich_app_with_swiftui

480.appl.mov

[Benjamin Mayo]

This should be fixed on master.