ReplaceDialogClassOptionRector

Replace removed $dialog_options['dialogClass'] with $dialog_options['classes']['ui-dialog'] in OpenDialogCommand / OpenModalDialogCommand / OpenOffCanvasDialogCommand constructors (removed in drupal:12.0.0)

-new \Drupal\Core\Ajax\OpenDialogCommand('#my-dialog', 'Title', $content, ['dialogClass' => 'my-class', 'width' => 600]);
+new \Drupal\Core\Ajax\OpenDialogCommand('#my-dialog', 'Title', $content, ['width' => 600, 'classes' => ['ui-dialog' => 'my-class']]);

Configure your rector.php:

<?php

use DrupalRector\Drupal11\Rector\Deprecation\ReplaceDialogClassOptionRector;
use Rector\Config\RectorConfig;

return RectorConfig::configure()
    ->withRules([
        ReplaceDialogClassOptionRector::class,
    ]);

Other rules in the drupal/core 11.3 set