Update repositories.txt (#6625)

Author: michaelnixonau

repositories.txt

@@ -294,6 +294,7 @@ https://github.com/zwieblum/ch32_deep_sleep
 https://github.com/microbotsio/CodeCell
 https://github.com/EduKits/ColourKit
 https://github.com/EduKits/ManagedButtons
+https://github.com/EduKits/UltraPing
 https://github.com/makkorjamal/PLSduino
 https://github.com/csl-3/Pasos
 https://github.com/devtagse/DEVTAGLibIA