How to properly connect PhantomJS?

Question

PhantomJS

I do everything according to the instructions, jonnnnyw.github.io/php-phantomjs/4.0/2-installation
PHP code looks like this

require '/var/www/html/vendor/autoload.php';
use JonnyW\PhantomJs\Client;
$client = Client::getInstance();

gives an error in response

Warning: Declaration of JonnyW\PhantomJs\DependencyInjection\ServiceContainer::load() should be compatible with Symfony\Component\DependencyInjection\Container::load($file) in /var/www/html/vendor/jonnyw/php-phantomjs/ src/JonnyW/PhantomJs/DependencyInjection/ServiceContainer.php on line 20

updated the system, php 7.3, according to the advice in composer.json indicated version 7.2, the error still remains.
Tell me who faced what can be done?