Consider taking USB fixes from Keyboardio's fork

[obra]

Hi folks,

We did significant work on USB in Keyboardio's fork of this core.

https://github.com/keyboardio/ArduinoCore-GD32-Keyboardio

If someone's interested and motivated, it's worth pulling those changes back to this one.

keyboardio#13 is one such chnage.

[maxgerhardt]

Are critical fixes changes in the underlying Gigadevice USB stack or on the layer above, in the Arduino core code? I have some contacts into Gigadevice if their code needs fixing.

[obra]

No idea if these were dealt with in more recent vendor firmware updates. (Since things work, we're not taking them by default)

https://github.com/keyboardio/ArduinoCore-GD32-Keyboardio/commits/main/system looks like the commits we made to their firmware libraries.