add Dell UltraSharp U3421WE (#235)
add Dell UltraSharp U3421WE (#235)

ref: https://www.dell.com/en-us/shop/dell-ultrasharp-34-curved-usb-c-hub-monitor-u3421we/apd/210-axqs/monitors-monitor-accessories
LeaVerou/dpi,LeaVerou/dpi