drupal 8 change password reset link
function my_module_menu_local_tasks_alter(&$data, $route_name) {
$data['tabs'][0]['node.extra_tab'] = array(
'#theme' => 'menu_local_task',
'#link' => array(
'title' => t('Extra tab'),
'url' => Url::fromUri('https://theurl.com', array('attributes' => array('target' => '_blank'))),
'localized_options' => array(
'attributes' => array(
'title' => t('Extra tab'),
),
),
),
);
}