brew运行慢是因为要从github上同步，这里可以使用清华的镜像

cd "$(brew --repo)"
git remote set-url origin https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/brew.git

cd "$(brew --repo)/Library/Taps/homebrew/homebrew-core"
git remote set-url origin https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/homebrew-core.git

brew update

tsinghua brew