Themeing the Instagram Light block photos

Problem/Motivation

How can I theme the output of the Instagram photos? Currently all photos are displayed using a for loop from the twig file instagram-lite-block.html.twig. Can I add bootstrap carousel markup to this twig file. Then create a patch of the changes? Is there a better way?
See example below, notice the added carousel attributes.

<div id="carouselExampleSlidesOnly" class="carousel slide instagram_gallery instagram_new insta-image-wr">
{% set image = {
'#theme':      'image',
'#uri':        post.media_url,
'#alt':        post.caption,
'#attributes': {'class':'insta-image', 'carousel-item'}