In #2916740: Add generic entity actions generic entity actions were introduced. In favor of that, the following action plugins are now deprecated:
Drupal\comment\Plugin\Action\PublishCommentDrupal\comment\Plugin\Action\UnpublishCommentDrupal\comment\Plugin\Action\SaveCommentDrupal\node\Plugin\Action\PublishNodeDrupal\node\Plugin\Action\UnpublishNodeDrupal\node\Plugin\Action\SaveNode
Existing plugins that extend one of the mentioned ones, should now extend Drupal\Core\Action\Plugin\Action\PublishAction, Drupal\Core\Action\Plugin\Action\UnpublishAction or Drupal\Core\Action\Plugin\Action\SaveAction.
Beside that, the content_moderation action plugins Drupal\content_moderation\Plugin\Action\ModerationOptOutPublishNode and Drupal\content_moderation\Plugin\Action\ModerationOptOutUnpublishNode are now deprecated in favor of Drupal\content_moderation\Plugin\Action\ModerationOptOutPublish and Drupal\content_moderation\Plugin\Action\ModerationOptOutUnpublish.
Comments
Example
If you - like me - don't initially know how to fix such deprecation notices, here an example:
If you have a plugin comment_publish_action, replace it with entity:publish_action:comment.
HTH!