How to show popover for item in ForEach in SwiftUI

Issue #618

Create custom Binding

List {
    ForEach(self.items) { (item: item) in
        ItemRowView(item: item)
            .popover(isPresented: self.makeIsPresented(item: item)) {
                ItemDetailView(item: item)
            }
    }
}

func makeIsPresented(item: Item) -> Binding<Bool> {
    return .init(get: {
        return self.selectedId == item.id
    }, set: { _ in
        self.selectedId = nil
    })
}