This PR plays catchup with some software versions!
- .nvmrc gets bumped to
14because 14 is the active LTS, and we were 4 major releases behind. - Multiple packages get bumped to their latest versions. Of note,
@11ty/eleventyis at12.0.1. This upgrade is a good idea because eleventy supports Node 10+ beginning at major version 12.
Bonus: The upgraded version of stylelint caught an error it previously overlooked. This PR fixes that.