code samples for rector.php don't match the auto-generated file

Also to note, "DrupalFinder" is saying the current rector.php file uses deprecated methods.

  $drupalFinder = new DrupalFinder();
  $drupalFinder->locateRoot(__DIR__);
  $drupalRoot = $drupalFinder->getDrupalRoot();

From the website https://github.com/webflo/drupal-finder, they recommend this code now:

$drupalFinder = new \DrupalFinder\DrupalFinderComposerRuntime();
$drupalRoot = $drupalFinder->getDrupalRoot();