You can enter the name without the dash first, and add the dash later.
Pasting seems to almost work too; it deletes the character after the `-` instead...
Not quite...
adafruit/Adafruit-GFX-Library doesn't work
adafruit/circuitpython-org works
No, entering the dash doesn't work. There's some funky js or something on the text box, and if you're looking for a repo with a "-" in it you have to paste it.
It also doesn't allow upper-case in the owner field.