update: fix fork bomb caused by `brew update --help`
update: fix fork bomb caused by `brew update --help`

Fixes #49334.

Closes #49343.

Signed-off-by: Xu Cheng <9a05244150b861e40c78843b801eed71bca54eac@me.com>

filcab/homebrew,filcab/homebrew,filcab/homebrew,filcab/homebrew