Update repositories.txt (#3637)

https://github.com/adafruit/Adafruit_FT5336

Author: ladyada

repositories.txt

@@ -2649,6 +2649,7 @@ https://github.com/adafruit/WaveHC
 https://github.com/adafruit/arduino-CAN
 https://github.com/adafruit/Adafruit_Debounce
 https://github.com/adafruit/Adafruit_ADS7830
+https://github.com/adafruit/Adafruit_FT5336
 https://github.com/adameat/MaximWire
 https://github.com/ademuri/esp-simple-web-dashboard
 https://github.com/ademuri/smart-input-filter