Update README

Author: dorranh

README.md

@@ -13,7 +13,7 @@ To build this sketch on the command line, you will need the following tools inst
 
   1. [make](https://www.gnu.org/software/make/) - Installation of `make` is OS-dependent. The provided link includes a download page for installing make on OSX and Linux. (See [here](https://stackoverflow.com/questions/32127524/how-to-install-and-use-make-in-windows) for more info on installing on Windows).
   1. [python3](https://www.python.org/downloads/) - Used internally by some of the Arduino libraries
-  1. [arduino_cli](https://arduino.github.io/arduino-cli/latest/)
+  1. [arduino-cli](https://arduino.github.io/arduino-cli/latest/)
 
 
 With those installed you can build the sketch with: