Support for Dates in UserDefaultsStorage

Add Persister/Persisted extensions on watchOS

• Add support for builder(for:) function to aid with building complex type (thanks to @randomeizer)
• Support for Xcode 12.1

The Xcode 12 beta includes Swift 5.3 but drops support for iOS 8.x. This means that Swift packages that support iOS 8 will cause a warning:

The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.0.99.

It's not possible to remove this warning within a project that depends on a Swift package with a deployment target of iOS 8, but it is possible to fix this in the dependency without removing support for iOS 8 for older versions of Swift. There are multiple way this can be accomplished.

Improve API for Subscription/Cancellable

Add documentation

I am currently maintaining numerous Swift Packages that don't receive a constant flow of updates, but do receive updates when new Swift updates come out, or as I think of useful additions.

To ensure that I can make some of these less frequent updates without too much friction and with confidence in their correctness I rely heavily on GitHub Actions, which I'll go over in this blog post.

Much better handling of optional values, which also allows for non-optional values

Release candidate 1 for 1.0 stable release

Has lots of tests but little documentation. API has changes a lot since initial 0.1.0 but I’m happy with it now. Hopefully it is consistent and (once docs are added) easy to use.