Allow config entities in Collections

Module page states the module can already collect config entities.. but it doesn't seem so.

At the moment, you can only add them programmatically. Here's a snippet from a project that does this:

$vocab = $this->entityTypeManager->getStorage('taxonomy_vocabulary')->create([
        'langcode' => 'en',
        'status' => TRUE,
        'name' => 'My taxonomy vocabulary',
        'vid' => 'my_taxonomy',
      ]);
      $vocab->save();

      if ($vocab) {
        // Add the vocab to this new collection.
        $collection_item_vocab = $this->entityTypeManager->getStorage('collection_item')->create([
          'type' => 'default',
          'collection' => 1,
          'canonical' => TRUE,
          'weight' => 10,
        ]);

        $collection_item_vocab->item = $vocab;
        $collection_item_vocab->save();
      }