Issue #3271144: Ensure new, changed or deleted service definitions are in the correct state after an update

package_manager/tests/fixtures/updated_module/1.0.0/src/PreUpdateService.php

-<?php
-
-namespace Drupal\updated_module;
-
-/**
- * A generic service class to prove that services are reloaded after an update.
- */
-class PreUpdateService {
-
-  /**
-   * Returns a string value.
-   *
-   * @return string
-   *   The string value.
-   */
-  public function myMethod(): string {
-    return 'PreUpdateService:myMethod()';
-  }
-
-}