Issue #3300245 by josh.fabean: Booking Instance update existing Instances to get titles

  \Drupal::entityDefinitionUpdateManager()

    ->installFieldStorageDefinition('title', 'bookable_calendar_opening_inst', 'bookable_calendar_opening_inst', $field_storage_definition);

}

/**

 * Update all Opening Instances to give them titles.

 */

function bookable_calendar_update_8111() {

  $all_openings = \Drupal::entityTypeManager()->getStorage('bookable_calendar_opening_inst')->loadMultiple();

  foreach ($all_openings as $opening) {

    $opening->save();

  }

}