Add Preferences (ygit#21)

Author: sindresorhus

README.md

@@ -197,6 +197,9 @@
     * 📦 Storage
 
     [Defaults — `@State` replacement for UserDefaults](https://github.com/sindresorhus/Defaults#swiftui-support)
+    * 👤 User Interface
+    
+    [Preferences — Create a preferences window for your macOS app in SwiftUI](https://github.com/sindresorhus/Preferences#swiftui-support)
 
 34. 📹 [Your First iOS and SwiftUI App - Ray Wenderlich](https://www.raywenderlich.com/4919757-your-first-ios-and-swiftui-app)
 35. 💻 [SVG to SwiftUI Shape Converter](https://github.com/quassummanus/SVG-to-SwiftUI)