I know a few people have already done that. There is another thread about updating screenshots and descriptions. I'd assume that the answer will be the same for both so if you want to play it safe, maybe you can wait for either thread to be clarified by staff.

StudioBlueJam Host3 minutes ago If itch.io allows you to change something (other than the actual game file itself, which it shouldn't), please do so if it'll help the judges find and understand your game prior to playing. There is no rule against that, and only fair. If you encounter anything truly "game breaking", let me know and I'll see what we can do on the admin side.

Sounds like it is okay.