Update repositories.txt

Fix "MatrixMini" (R3) repo link

Author: a10036gt

repositories.txt

@@ -2333,7 +2333,6 @@ https://github.com/franeum/TI_SN76489
 https://github.com/FrankBoesing/FastCRC
 https://github.com/frankjoshua/rosserial_arduino_lib
 https://github.com/Franzininho/Franzininho_LiquidCrystal
-https://github.com/frason5566/MatrixMini
 https://github.com/Fraunhofer-IMS/AIfES_for_Arduino
 https://github.com/freaklabs/cmdArduino
 https://github.com/Fredi/ArduinoIRC