Configuring the zoom factor in the video capture device.

SetZoom.swift

    public func set(zoom: CGFloat){
        let factor = zoom < 1 ? 1 : zoom
        let device = self.videoDeviceInput.device
        
        do {
            try device.lockForConfiguration()
            device.videoZoomFactor = factor
            device.unlockForConfiguration()
        }
        catch {
            print(error.localizedDescription)
        }
    }