Just use the itch.io app. It will update it automatically!
Having to use a non Mac certificated app only in order to run the game is a bad idea in first place - for many Mac users which destain non Mac store games in first place. That's the reason why Steam is not famous for Mac user. If they buy offside the Mac store your game (as I do) the despise additional apps just to to be able to run the game
- my 2 cents - an I'm an Apple user since 1984