It would be better to update the script 😀 . Unless it's a one-off thing in which case better to just run it on a local machine.
WordOps supports php7.2 as a minimum, so it's not straightforward. You'd need to install php7.0 independently of WordOps (lots of guides via Google), and then customise your site config (wo site edit yourdomain.com) to use the older version (either at the site level or for a specific directory).