Leif/update supported platforms (#47)

* Update code for new supported platforms

* Update README with new supported platforms

Package.swift

@@ -5,10 +5,10 @@ import PackageDescription
 let package = Package(
     name: "AppState",
     platforms: [
-        .iOS(.v16),
-        .watchOS(.v9),
-        .macOS(.v13),
-        .tvOS(.v16)
+        .iOS(.v15),
+        .watchOS(.v8),
+        .macOS(.v11),
+        .tvOS(.v15)
     ],
     products: [
         .library(

README.md

@@ -10,7 +10,7 @@ AppState is a Swift Package that simplifies the management of application state
 
 - **StoredState:** Dedicated struct type for encapsulating and broadcasting stored value changes within the app's scope. Values are stored using `UserDefaults`.
 
-- **SyncState:** Dedicated struct type for encapsulating and broadcasting stored value changes within the app's scope. Values are stored using `iCloud`.
+- **SyncState:** Dedicated struct type for encapsulating and broadcasting stored value changes within the app's scope. Values are stored using `iCloud`. Requires iOS 15.0, watchOS 9.0, macOS 11.0, or tvOS 15.0.
 
 - **Dependency:** Dedicated struct type for encapsulating dependencies within the app's scope.
 
@@ -20,18 +20,18 @@ AppState is a Swift Package that simplifies the management of application state
 
 - **StoredState (property wrapper):** A property wrapper that stores its values to `UserDefaults`. Works the same as `AppState` otherwise.
 
-- **SyncState (property wrapper):** A property wrapper that stores its values to `iCloud`. Works the same as `AppState` otherwise.
+- **SyncState (property wrapper):** A property wrapper that stores its values to `iCloud`. Works the same as `AppState` otherwise. Requires iOS 15.0, watchOS 9.0, macOS 11.0, or tvOS 15.0.
 
 - **AppDependency (property wrapper):** A property wrapper that simplifies the handling of dependencies throughout your application.
 
 ### Requirements
 
 - Swift 5.7 or later
 
-- iOS 16.0 or later
-- watchOS 9.0 or later
-- macOS 13.0 or later
-- tvOS 16.0 or later
+- iOS 15.0 or later
+- watchOS 8.0 or later
+- macOS 11.0 or later
+- tvOS 15.0 or later
 
 ## Getting Started