IAP Not working for MacOS Application

### Platform
- [ ] macOS

### In app purchase type

- [ ] Auto-Renewable Subscription

### Environment

- [ ] Sandbox

### Version
0.13.0

## Report

### Issue summary
In App Purchase not working for MacOS application. Actually Nothing happen when I call `SwiftyStoreKit.purchaseProduct("com.ca.plagChecker.business", quantity: 1, atomically: true) { result in}`
This product is not purchased according to this function SwiftyStoreKit.verifyReceipt

### What did you expect to happen
When I call purchaseProduct function, it should purchase or throw an error.

### What happened instead
Nothing happens, no success no error. I am just like lost somewhere.