brew_upgrade: Upgrade outdated packages
In briandconnelly/homebrew: Install and Manage Packages using 'Homebrew'

brew_upgrade() upgrades outdated casks and outdated, unpinned formulae using the same options they were originally installed with, plus any appended brew formula options.

1	brew_upgrade(...)

...

Arguments passed on to brew_cmd

cmd: The command to run (e.g., install)
args: Additional arguments for the command
brew_cmd: Optional: Location of brew command.
echo: Whether to print output and error messages to the screen. Defaults to TRUE for interactive sessions.