Suppress Brew update to speed up the step

Description of the feature request

Related to step: steps-brew-install (No update 路 Issue #9 路 bitrise-steplib/steps-brew-install 路 GitHub )

It would be nice to have a built in way to suppress brew from updating itself, which is controlled with the HOMEBREW_NO_AUTO_UPDATE=1 env. This would speed up the step considerably.

Use case / for what or how I would use it

Any workflow with a brew install step.