Update repositories.txt (#5573)

Author: krosDC

repositories.txt

@@ -16,6 +16,7 @@ https://github.com/DigitalCodesign/MentorBit-PoteLineal
 https://github.com/DigitalCodesign/MentorBit-Potenciometro
 https://github.com/DigitalCodesign/MentorBit-PoteRueda
 https://github.com/DigitalCodesign/MentorBit-Pulsadores
+https://github.com/DigitalCodesign/MentorBit-RGB
 https://github.com/median-dispersion/Non-Blocking-Melody
 https://github.com/jobitjoseph/ESPWebFileManager
 https://github.com/playfultechnology/PN5180