Add submission # 5556

#5556

Author: ArduinoBot

registry.txt

@@ -7674,3 +7674,4 @@ https://github.com/rei-vilo/PDLS_EXT4_Basic_Matter.git|Contributed|PDLS_EXT4_Bas
 https://github.com/ripred/CodeSizeProfiler.git|Contributed|CodeSizeProfiler
 https://github.com/DigitalCodesign/MentorBit-1Rele.git|Contributed|MentorBit-1Rele
 https://github.com/DigitalCodesign/MentorBit-2Rele.git|Contributed|MentorBit-2Rele
+https://github.com/DigitalCodesign/MentorBit-3LED.git|Contributed|MentorBit-3LED