Update repositories.txt (#5379)

Arduino library for the HX710A and HX710B 24-Bit ADC.

Author: RobTillaart

repositories.txt

@@ -5325,6 +5325,7 @@ https://github.com/RobTillaart/HeartBeat
 https://github.com/RobTillaart/Histogram
 https://github.com/RobTillaart/HMC6352
 https://github.com/RobTillaart/HT16K33
+https://github.com/RobTillaart/HX710AB
 https://github.com/RobTillaart/HX711
 https://github.com/RobTillaart/HX711_MP
 https://github.com/RobTillaart/I2C_24LC1025