/**
 * Implements hook_form_FORM_ID_alter().
 */
function mm_form_node_foo_form_alter(&$form, DrupalCoreFormFormStateInterface $form_state, $form_id)
{
    $form['#attached']['library'][] = 'google/maps';
}

google.maps:
  js:
    https://maps.googleapis.com/maps/api/js?key=API_KEY&libraries=places&callback=initMap: {type: external, attributes: { defer: true, async: true, data-test: map-link } } }