You can disable deprecation warnings from PHP to fix this issue. As @ref2 mentioned you can put this in your php.ini, or in your file using

error_reporting(E_ERROR | E_WARNING | E_PARSE | E_NOTICE);

or

error_reporting(E_ALL ^ E_DEPRECATED);

Source: https://stackoverflow.com/a/2803783/22557063

Since this is a Laravel app, I would recommend placing this in your AppServiceProvider (See docs).

If that doesn't work, you might consider placing it at the beginning of the artisan file, e.g. here. That should solve the deprecation message being displayed when running artisan commands