Add DrupalCI file to config_override.

Closes #3446082

src/ConfigOverrideServiceProvider.php

@@ -17,7 +17,7 @@ class ConfigOverrideServiceProvider implements ServiceModifierInterface {
    */
   public function alter(ContainerBuilder $container) {
     if (class_exists('\Symfony\Component\Dotenv\Dotenv')) {
-      $drupal_root = $container->has('app.root') ? $container->getParameter('app.root') : DRUPAL_ROOT;
+      $drupal_root = $container->hasParameter('app.root') ? $container->getParameter('app.root') : DRUPAL_ROOT;
       $dotenv = new Dotenv();
       $all_config_overrides = [];
       $possible_files = [