Resolve #3490037 "Min drupal 10.3"

Closes #3490037

src/Plugin/Block/PrivateMessageActionsBlock.php

@@ -4,11 +4,13 @@ namespace Drupal\private_message\Plugin\Block;
 
 use Drupal\Core\Access\AccessResult;
 use Drupal\Core\Access\AccessResultInterface;
+use Drupal\Core\Block\Attribute\Block;
 use Drupal\Core\Block\BlockBase;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\Core\Session\AccountProxyInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\Core\Url;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
@@ -16,13 +18,12 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  * Provides the private message actions block.
  *
  * This block holds links to perform actions on a private message thread.
- *
- * @Block(
- *   id = "private_message_actions_block",
- *   admin_label = @Translation("Private Message Actions"),
- *   category =  @Translation("Private Message"),
- * )
  */
+#[Block(
+  id: 'private_message_actions_block',
+  admin_label: new TranslatableMarkup('Private Message Actions'),
+  category: new TranslatableMarkup('Private Message'),
+)]
 class PrivateMessageActionsBlock extends BlockBase implements ContainerFactoryPluginInterface {
 
   public function __construct(