Xcode 11 で作成したプロジェクトを iOS 13 未満に対応させる

import UIKit

@available(iOS 13.0, *)
class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?

    〜省略〜

}

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    〜省略〜

    // MARK: UISceneSession Lifecycle

    @available(iOS 13.0, *)
    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Called when a new scene session is being created.
        // Use this method to select a configuration to create the new scene with.
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    @available(iOS 13.0, *)
    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
        // Called when the user discards a scene session.
        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
    }


}

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    〜省略〜
}