Build Watch Complications in SwiftUI.

This is a sample Watch App to check implementation of SwiftUI's Complecation.
This app was checked CLKComplicationTemplateGraphicRectangularFullView.

I wrote an article about this app as an article of Qiita Advent Calendar.
My article is as follow.(In Japanese🙏)

https://qiita.com/MilanistaDev/items/a2325ce916f625aa1d44