Update repositories.txt

Author: GyverLibs

repositories.txt

@@ -2695,6 +2695,7 @@ https://github.com/gvandersel/SXAccessoire
 https://github.com/GypsyRobot/CuteBuzzerSounds
 https://github.com/GypsyRobot/Formulinha
 https://github.com/GypsyRobot/MusicBuzzer
+https://github.com/GyverLibs/GyverMIDI
 https://github.com/GyverLibs/GTimer
 https://github.com/GyverLibs/BSON
 https://github.com/GyverLibs/Looper