Set window in demo app AppDelegate to avoid SVProgressHUD crash

Author: mokagio

Demo/AuthenticatorDemo/AppDelegate.swift

@@ -3,6 +3,13 @@ import UIKit
 @main
 class AppDelegate: UIResponder, UIApplicationDelegate {
 
+    // This is a property defined in `UIApplicationDelegate`. In modern UIKit apps,
+    // `UISceneConfiguration` is responsible for creating and holding the window.
+    //
+    // However, we need to set this anyway because SVProgressHUD accesses it internally and will
+    // crash the app if the value it finds is nil.
+    var window: UIWindow?
+
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
         return true
     }

Demo/AuthenticatorDemo/SceneDelegate.swift

@@ -10,5 +10,8 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
         window = UIWindow(windowScene: scene)
         window?.rootViewController = UINavigationController(rootViewController: ViewController())
         window?.makeKeyAndVisible()
+
+        // We need to set this relationship to avoid a crash when using SVProgressHUD.
+        (UIApplication.shared.delegate as? AppDelegate)?.window = window
     }
 }