【iOS】根据不同的设备方向设置不同的label格式

参考：Stanford Swift CS193P 10.Multithreading and Autolayout

private func updateFlipCountLabel() {
	let attributes: [NSAttributedStringKey:Any] = [
		.strokeWidth : 5.0
		.strokeColor : black
	]
	let attributedString = NSAttributedString(
		string: traitCollection.verticalSizeClass == .compact ? "Flips\n\(flipCount)" : 
			"flips: \(flipCount)",
		attributes: attributes
	)
	flipCountLabel.attributedText = attributedString
}

override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
	super.traitCollectionDidChange(previousTraitCollection)
	updateFlipCountLabel()
}