message: patch: fix usb-device-boot link in README
  Change-type: patch
diff: Etcher is a powerful OS image flasher built with web technologies to ensure
  flashing an SDCard or USB drive is a pleasant and safe experience. It protects
  you from accidentally writing to your hard-drives, ensures every byte of data
  -was written correctly, and much more. It can also directly flash Raspberry Pi devices that support [USB device boot mode](https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/device.md).
  +was written correctly, and much more. It can also directly flash Raspberry Pi devices that support [USB device boot mode](https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#usb-device-boot-mode).
  [![Current Release](https://img.shields.io/github/release/balena-io/etcher.svg?style=flat-square)](https://balena.io/etcher)
  [![License](https://img.shields.io/github/license/balena-io/etcher.svg?style=flat-square)](https://github.com/balena-io/etcher/blob/master/LICENSE)
  