www/ruby-jekyll-feed: update to 0.16.0

0.16.0 (2022-01-03)

Minor Enhancements

* Add support for page.description in front matter to become entry <summary>
  (#297)

Bug Fixes

* Fold private methods into the :render method as local variables (#327)
* Check post.categories instead of post.category (#357)
* Switched xml_escape for <![CDATA[]]> for post content (#332)

Development Fixes

* Add Ruby 3.0 to CI (#337)
* Lock RuboCop to v1.18.x (#348)
* Add workflow to release gem via GH Action (#355)

Documentation

* Use .atom extension in documented examples since we write an Atom feed
  (#359)

(taca)