$ brew install alphagov/gds/gds-cli
==> Installing gds-cli from alphagov/gds
Error: No available formula with the name "homebrew/cask/aws-vault" (dependency of alphagov/gds/gds-cli)
Found a cask named "homebrew/cask/aws-vault" instead.
Did you mean to type "brew cask install homebrew/cask/aws-vault"?

$ brew install homebrew/cask/aws-vault
==> brew cask install homebrew/cask/aws-vault
...