thanx for this useful plugin. I've used it several times from the WP Dashboard (Tools > Plugin Check). Today I tried the WP_CLI wp plugin check command for the first time.
It would be helpful if the check command output a WP_CLI::success() message if no errors/warnings are found. The way things are it is not possible to know whether there were no errors/warnings or whether there was a run-time fatal while the check command was running (without consulting the PHP error log).
Not sure how such a message might affect the GitHub Action, as I don't use GH actions ;-)
If there is consensus that this would be a good idea, I'm happy to do a PR.