swift 修改系统tabbar

tabBar.tintColor = UIColor(r: 70, g: 89, b: 255)
tabBarItem.imageInsets = UIEdgeInsets(top: -8, left: 0, bottom: 3, right: 0)
if #available(iOS 13.0, *) {
        let appearance = UITabBarAppearance()
        let normal = appearance.stackedLayoutAppearance.normal
        normal.titlePositionAdjustment = UIOffset(horizontal: 0,vertical: -5)
         self.tabBar.standardAppearance = appearance
  }