Replace zsh-completion by zsh-completions in brew

[Arrows78]

Hello,

Thanks for your dotfiles, it's really impressive, and easy to configure based on each choice.

Context By checking your repo, I saw this line, and it seems that the brew package for ZSH Completions is incorrect. Even if the old command probably still work anyway.

https://github.com/aaronbates/dotfiles/blob/c88d01c58839f331a19d0512202e9adbe77af545/setup/brew.sh#L76

To Do Replace zsh-completions by zsh-completions

Source: https://formulae.brew.sh/formula/zsh-completions