Change to attribute technique

src/Plugin/Block/ArchiveTreeBlock.php

@@ -3,18 +3,18 @@
 namespace Drupal\archive_tree\Plugin\Block;
 
 use Drupal\Core\Block\BlockBase;
+use Drupal\Core\Block\Attribute\Block;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\node\Entity\NodeType;
 
 
 /**
- * Provides an 'Archive tree' block.
- *
- * @Block(
- *   id = "archive_tree_block",
- *   admin_label = @Translation("Archive tree"),
- * )
+ * Provides an 'Archive Tree' block.
  */
+#[\Drupal\Core\Block\Annotation\Block(
+  id: "archive_tree_block",
+  admin_label: ["Archive tree"]
+)]
 
 class ArchiveTreeBlock extends BlockBase {
   /**