Experiment to see if there's a better way of managing chromedriver versions with Homebrew.
This isn't the proper way to version since switch doesn't work... still learning and YMMV. But potentially useful anyway.
brew tap gpaciga/homebrew-chromedriver
First make sure you have the latest versions:
brew update
To install a specific version of chromedriver:
brew cask install chromedriver73
Or, if you've previously installed this version, you may need to use reinstall instead:
brew cask reinstall chromedriver73
Should result in something like:
$ chromedriver --version
ChromeDriver 73.0.3683.68 (47787ec04b6e38e22703e856e101e840b65afe72)
Versions are cloned from https://github.com/Homebrew/homebrew-cask/blob/master/Casks/chromedriver.rb.