Generating invalid (empty) podcast:chapters elements

Hi there, nice to see this plugin support the new podcast namespace tags.

I came across a public podcast feed generated using this plugin with some invalid chapter tags:

👉 https://members.lcg.org/feeds/podcasts/sermons-audio-last-5.xml

<podcast:chapters type="application/json+chapters"/>

Looking again at the feed contents I see a few other bad ones such as <podcast:season/> and <podcast:episode/>

Ideally the CMS would elide these from the output feed xml if not present. Sorry I don't know the version since it's not my site. Is there a well to tell from the outside?

Let me know if you have any questions, thanks!
- John