Maintenance release for Xcode 14

• The minimum deployment target has been bumped to iOS 12, tvOS 12 and watchOS 5.
• This release makes sure the project builds with Xcode 14 without any significant warning.

SPM support

• This release introduces Swift Package Manager (SPM) support, replacing Carthage entirely. To migrate your project please follow instructions for migrating to version 6 of our Letterbox library.
• The library is compatible with Catalyst.

iOS 13, tvOS and watchOS support

• This release makes sure the project runs fine on iOS 13 and builds with Xcode 11 without any significant warning.
• The framework can be used in tvOS and watchOS applications.

Update to official version 0.6 and static framework support

• Updated to the new official version 0.6.
• To mitigate slow application startups usually associated with a large number of dynamic frameworks being used, static framework integration with Carthage 0.30 and above is now supported.

Initial SRG release

This version is based on the official libextobjc library version 0.5, with minor adjustments for better integration with newer Xcode versions and Carthage.