Xendrez

Added Package.swift for swift packages

PaywallActivity doesn't implement all methods in PaywallListener

6

- [x] I have updated Purchases SDK to the latest version - [x] I have read the [Contribution Guidelines](https://github.com/RevenueCat/purchases-android/blob/main/CONTRIBUTING.md) - [x] I have searched the [Community](https://community.revenuecat.com) - [x] I have...

To use Swift package manager, there needs to be a new release to fix the build issues due to XCode 14. The code has been fixed, but no release done.