Add submission # 6999

#6999

Author: ArduinoBot

registry.txt

@@ -8432,3 +8432,4 @@ https://github.com/AymenTurki0/Aerobotix_Arduino_navigation.git|Contributed|Aero
 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
+https://github.com/dejwk/roo_blink.git|Contributed|roo_blink