iOS version dropped reminder

Here’s the code if you want to experiment with it:

import UIKit

@available(iOS, deprecated: 14)
func warningOnceiOS13IsDropped(_ message: String) { }

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        warningOnceiOS13IsDropped("remove once we drop iOS 13")

        /* some workaround for an iOS 13 bug */
    }
}