Test Application from lesson 3.01
An application in which you can switch traffic signals. At the first start, the color of each traffic light is off. When the START button is pressed, the red light turns on and the button title changes to NEXT. Subsequent pressing of the "NEXT" button changes the active color to the next one in order. Thus, each subsequent press of the "Next" button sequentially changes the traffic lights. The application is built on SwiftUI.
