Add audio_url post meta to new podcast

add_audio_url_meta_to_podcast.php

<?php
add_action(
  "gatographql__executed_query:ImportPostFromRSSFeed",
  function (Response $response) {
    /** @var string */
    $responseContent = $response->getContent();
    /** @var array<string,mixed> */
    $responseJSON = json_decode($responseContent, true);
    $postID = $responseJSON['data']['createPost']['post']['id'] ?? null;
    if ($postID === null) {
      // Do nothing
      return;
    }

    // Complete here
    $audioURL = '...';
    add_post_meta($postID, 'audio_url', $audioURL, true);
  }
);