Add a field for the HTML tag count.
function tmgmt_update_8001() {
$storage_definition = BaseFieldDefinition::create('integer')
->setLabel(t('Tags count'))
->setSetting('unsigned', TRUE);
\Drupal::entityDefinitionUpdateManager()
->installFieldStorageDefinition('tags_count', 'tmgmt_job_item', 'tmgmt', $storage_definition);
$storage_definition = BaseFieldDefinition::create('integer')
->setLabel(t('Tags count'))
->setDescription(t('HTML tags count provided by the remote service.'));
\Drupal::entityDefinitionUpdateManager()
->installFieldStorageDefinition('tags_count', 'tmgmt_remote', 'tmgmt', $storage_definition);
}