Drupal 8: Altering the actions available for a node form, either add or edit.

alter_node_form.php

<?php

function hook_MY_MODULE_form_alter(){

  // Altering the actions available for a node form, either add or edit.
  $build_info = $form_state->getBuildInfo();
  if (isset($build_info['base_form_id']) && $build_info['base_form_id'] == 'node_form') {
    $form_object = $form_state->getFormObject();
    $entity = $form_object->getEntity();
    $bundle = $entity->bundle();

    // Any bundle key added here, will have unpublish option, else action is removed.
    $allowed_bundles = [
      'article',
    ];

    if (!in_array($bundle, $allowed_bundles)) {
      unset($form['actions']['unpublish']);
    }
  }
}