Update README.md

Author: fpistm

README.md

@@ -93,6 +93,7 @@ User can add a STM32 based board following this [wiki](https://github.com/stm32d
  * [RemRam v1](https://github.com/hasenbanck/remram)
 
  * STM32L0
+ * [Nucleo L073RZ](http://www.st.com/en/evaluation-tools/nucleo-l073rz.html)
  * [RAK811 LoRa Tracker](https://www.rakwireless.com/en/) (Basic support)
 
  * STM32L4