Update repositories.txt (#4548)

Author: ladyada

repositories.txt

@@ -210,6 +210,7 @@ https://github.com/adafruit/Adafruit_CAN
 https://github.com/adafruit/Adafruit_CAP1188_Library
 https://github.com/adafruit/Adafruit_CC3000_Library
 https://github.com/adafruit/Adafruit_CCS811
+https://github.com/adafruit/Adafruit_CH9328
 https://github.com/adafruit/Adafruit_CircuitPlayground
 https://github.com/adafruit/Adafruit_CompositeVideo
 https://github.com/adafruit/Adafruit_CPFS