docs(versions): Dynamically determine latest stable & deprecated (#203)

* docs(versions): Automatically determine latest stable & deprecated

This removes the need to add a tag `deprecated` to previous versions
during the release process.
Before this change when 1.27.1 is released, 1.27.0 changelog file needs
to be updated with `deprecated` tag.

Overall we can do this by leveraging some key ideas:
1. changelog's contain a `date: 2022-05-02 23:37:12 +0000` section in
   frontmatter that is never changed. This means a newer patch version
   for any `{major.minor}` will always have a newer `date`.
2. we only commit to maintaining (backporting) the latest
   3 {major.minor} versions/branches.

* docs(versions): Remove unnecessary deprecated tag in changelogs

* chore(netlify): Bump HUGO version

* Revert "chore(netlify): Bump HUGO version"

This reverts commit fc318ea.

* docs(versions): format per older hugo version

* docs(versions): only lookup changelogs, not index

Author: kskewes-sf

.gitignore

@@ -24,3 +24,5 @@ themes/**
 .netlify
 
 .idea/
+
+.hugo_build.lock