Try renaming the osu! 2.app application on your Desktop to osu!.app and then run the command again. When you dragged the file into the Terminal there was a leading space which might have caused it to fail.
One additional to thing to try is running this command while you are cded into the Desktop in Terminal:
chmod -R +x 'osu!.app'
(You probably don't need to update the WineskinLauncher itself. It's not usually the component that needs to be updated; That "Waiting to Update" message is from your iCloud Drive waiting to upload the file.)
One additional to thing to try is running this command while you are cded into the Desktop in Terminal:
chmod -R +x 'osu!.app'
(You probably don't need to update the WineskinLauncher itself. It's not usually the component that needs to be updated; That "Waiting to Update" message is from your iCloud Drive waiting to upload the file.)