Add submission # 306

#306

Author: ArduinoBot

registry.txt

@@ -4221,3 +4221,4 @@ https://github.com/khoih-prog/ESP32_C3_TimerInterrupt.git|Contributed|ESP32_C3_T
 https://github.com/PowerBroker2/MotorController.git|Contributed|MotorController
 https://github.com/FTTechBrasil/AqualaboSensor.git|Contributed|FTTech Aqualabo Sensors
 https://github.com/guttih/DisplayMenu.git|Contributed|DisplayMenu
+https://github.com/noah1510/unit-system-adruino.git|Contributed|unit-system