Update repositories.txt

AirNgin · web-flow · commit a1b38c7373cb · 2025-08-23T20:59:23.000+03:30
Add AirNgin STM32 MQTT Client library
diff --git a/repositories.txt b/repositories.txt
@@ -7677,3 +7677,4 @@ https://github.com/marekburiak/ESP32_MQTTClient
 https://github.com/levkovigor/PTZProtocolHandler
 https://github.com/Alex-Stone-Github/pepstep
 https://github.com/AirNgin/Airngin-esp32-mqtt-client
+https://github.com/AirNgin/Airngin-stm32-mqtt-client
