Previously in SwiftUI (Xcode Beta 5), a modal worked like this:

```swift
struct ContentView: View {

    @State var modalIsPresented: Bool = false

    var body: some View {

        Button(action: {

            self.modalIsPresented = true

        }) {

            Text("Show modal")

        }

        .sheet(isPresented: $modalIsPresented, content: {

            ModalView()

        })

    }

}

struct ModalView: View {

    @Environment(\.presentationMode) var presentationMode

    var body: some View {

        Button(action: {

            self.presentationMode.value.dismiss()

        }) {

            Text("Hide modal")

        }

    }

}

```

But now in Xcode Beta 6, I cannot find a way to dismiss a modal. There no longer is a `value` property of `presentationMode`, and the other properties don't seem to have any useful methods I can use.

How do you dismiss a SwiftUI modal in Xcode Beta 6?