如何在动画中更改UIBezierPath笔触的颜色？

// 创建CAShapeLayer对象
let shapeLayer = CAShapeLayer()
// 将shapeLayer添加到视图的layer中
view.layer.addSublayer(shapeLayer)

// 创建UIBezierPath对象
let bezierPath = UIBezierPath(rect: CGRect(x: 0, y: 0, width: 100, height: 100))

// 设置CAShapeLayer的path属性
shapeLayer.path = bezierPath.cgPath

// 设置CAShapeLayer的strokeColor属性为初始颜色
shapeLayer.strokeColor = UIColor.red.cgColor

// 创建CABasicAnimation对象
let animation = CABasicAnimation(keyPath: "strokeColor")
// 设置动画的起始值和结束值
animation.fromValue = UIColor.red.cgColor
animation.toValue = UIColor.blue.cgColor
// 设置动画的持续时间
animation.duration = 1.0

// 将动画添加到CAShapeLayer中
shapeLayer.add(animation, forKey: "strokeColor")