Fixed firmware repository link

README.md

@@ -1,6 +1,6 @@
 # High autonomy GPS tracker.
 
-A custom Arduino 2 layers board done with [Kicad](http://kicad-pcb.org/) meant to be use with a dedicated [firmware](https://github.com/blemasle/arduino-gpstracker). The result is a high autonomy GPS tracker that can be use to track moving vehicules.
+A custom Arduino 2 layers board done with [Kicad](http://kicad-pcb.org/) meant to be use with a dedicated [firmware](https://github.com/blemasle/gpstracker-firmware). The result is a high autonomy GPS tracker that can be use to track moving vehicules.
 
 <img alt="Board front" src="https://raw.githubusercontent.com/blemasle/gpstracker-board/assets/board-front.png" width="45%"></img> <img alt="Board back" src="https://raw.githubusercontent.com/blemasle/gpstracker-board/assets/board-back.png" width="45%"></img>