Support for nightly in Brewfile (or upgrading nightly without --greedy-latest)

[tammersaleh]

I use a Brewfile to install/upgrade all of the apps on my MacBook, including wezTerm nightly:

https://github.com/tammersaleh/dotfiles-public/blob/70e6ff1e7621028e30953eb6a1ca05a088d12189/.Brewfiles/Darwin.rb#L48

But this doesn't pickup the upgrades. Instead, I have to manually run:

https://github.com/wez/wezterm/blob/6658ee773009f4df0f628f8fcb3084db29244353/docs/install/macos.md?plain=1#L42

I don't suppose there's a way to have both the nightly and a normal upgrade process? ie: I'd like to just run brew upgrade without the --greedy-latest.

[wez]

I don't use brew enough to sit down and figure this out, but I'm open to a PR