Add submission # 6998

#6998

Author: ArduinoBot

registry.txt

@@ -8433,3 +8433,4 @@ https://github.com/ababdelo/ESPDiscordClient.git|Contributed|ESP Discord Client
 https://github.com/AymenTurki0/Aerobotix_Arduino_navigation.git|Contributed|Aerobotix_Arduino_nav
 https://github.com/m5stack/M5Module-4EncoderMotor.git|Contributed|M5Module-4EncoderMotor
 https://github.com/mathieucarbou/MycilaDimmer.git|Contributed|MycilaDimmer
+https://github.com/gvp-257/DietSerial.git|Contributed|DietSerial