brew cask outdated -> brew cask cleanup --outdated

[att14]

Here is the change in homebrew. Homebrew/homebrew-cask#9478

[ratson]

@msanders would you have time to review the change?

[msanders]

Unfortunately these two commands don't seem to be equivalent. brew cask outdated used to return a list of outdated formulas (as in brew outdated), whereas brew cask cleanup --outdated just removes the cache. I'll have to look into this in more detail to see if we can continue to support this behavior with homebrew-cask, might just have to drop it.

[RogerThiede]

Would it be easy to simply drop this feature now while others look into workarounds to keep supporting the behavior?
Cider can't be used to bootstrap a new system since cider restore hasn't worked. I'm trying to investigate if it's possible to revert to a very old version of brew in order to freshly bootstrap a new system.