git-extras: disable its own updater and redirect users to Homebrew
git-extras: disable its own updater and redirect users to Homebrew

Closes #44521.

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

kwilczynski/homebrew,kwilczynski/homebrew,kwilczynski/homebrew,kwilczynski/homebrew