cmd/info: Add support for casks in brew info

[whoiswillma]

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Allow references to casks in brew info, e.g. brew info firefox sl.

• Add support for --json for casks

Using brew outdated as prior art: #7927

I added --json=v2 which outputs a json dictionary with keys for formulae and casks.

• Deprecate brew cask info (any more functionality to move over besides --json?)

[MikeMcQuaid]

Looking good so far, nice work!

[MikeMcQuaid]

Makes sense to me, thanks @whoiswillma!