Ah yes, this is a problem introduced by the new OSX update (safety feature). I am currently investigating that, as it prevents me from even opening up the game with Godot Engine on MacOS!
For a short-term fix, please try Step 4 on here: https://osxdaily.com/2019/02/13/fix-app-damaged-cant-be-opened-trash-error-mac/ it helped me, too