Resolve #3438428 "Automated drupal 11"

Closes #3438428

src/Plugin/Field/FieldWidget/InlineEntityFormBase.php

@@ -112,7 +112,7 @@ abstract class InlineEntityFormBase extends WidgetBase implements ContainerFacto
   /**
    * {@inheritdoc}
    */
-  public function __sleep() {
+  public function __sleep(): array {
     $keys = array_diff(parent::__sleep(), ['inlineFormHandler']);
     return $keys;
   }
@@ -120,7 +120,7 @@ abstract class InlineEntityFormBase extends WidgetBase implements ContainerFacto
   /**
    * {@inheritdoc}
    */
-  public function __wakeup() {
+  public function __wakeup(): void {
     parent::__wakeup();
     $this->createInlineFormHandler();
   }