NotificationBuilder.Notify under Android 12 crashes

[ChristianM66]

NotificationBuilder.Notify (Android.App.Activity activity, Plugin.Toasts.INotificationOptions options)
Java.Lang.IllegalArgumentException: com.ist.saleboard.mobile: Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent. Strongly consider using FLAG_IMMUTABLE, only use FLAG_MUTABLE if some functionality depends on the PendingIntent being mutable, e.g. if it needs to be used with inline replies or bubbles.