Add submission # 6830

#6830

Author: ArduinoBot

registry.txt

@@ -8306,3 +8306,4 @@ https://github.com/m5stack/M5Unit-Miniscale.git|Contributed|UNIT_MINISCALE
 https://github.com/derdoktor667/DShotRMT.git|Contributed|DShotRMT
 https://github.com/EnviroDIY/ANBSensorsModbus.git|Contributed|ANBSensorsModbus
 https://github.com/7semi-solutions/7Semi-HMC6343-3-Axis-Digital-Compass-Module-with-Tilt-Compensation-I2C-Arduino-Library.git|Contributed|7Semi HMC6343 Compass
+https://github.com/AirNgin/Airngin-stm32-mqtt-client.git|Contributed|AirNgin_STM32_MQTT_Client