Add Sendable conformance (#235)

Author: Widcket

SimpleKeychain/Accessibility.swift

@@ -1,7 +1,7 @@
 import Security
 
 /// Represents the accessibility types of Keychain items. It's a mirror of `kSecAttrAccessible` values.
-public enum Accessibility: RawRepresentable {
+public enum Accessibility: RawRepresentable, @unchecked Sendable {
 
     /// The data in the Keychain item can be accessed only while the device is unlocked by the user.
     /// See [kSecAttrAccessibleWhenUnlocked](https://developer.apple.com/documentation/security/ksecattraccessiblewhenunlocked).

SimpleKeychain/SimpleKeychain.swift

@@ -1,7 +1,7 @@
 import Foundation
 import Security
 #if canImport(LocalAuthentication)
-import LocalAuthentication
+@preconcurrency import LocalAuthentication
 #endif
 
 typealias RetrieveFunction = (_ query: CFDictionary, _ result: UnsafeMutablePointer<CFTypeRef?>?) -> OSStatus
@@ -10,7 +10,7 @@ typealias RemoveFunction = (_ query: CFDictionary) -> OSStatus
 /// A simple Keychain wrapper for iOS, macOS, tvOS, and watchOS.
 /// Supports sharing credentials with an **access group** or through **iCloud**, and integrating
 /// **Touch ID / Face ID**.
-public struct SimpleKeychain {
+public struct SimpleKeychain: @unchecked Sendable {
     let service: String
     let accessGroup: String?
     let accessibility: Accessibility