Add changelog to track document changes

[wareid]

Add a changelog section to the end of the document outlining the details of major changes (i.e. substantive changes to text). This could accompany version releases and would only need to summarize the text change. Could link to the release information in GH, but serves as a quick reference within the document for those less comfortable with GH and navigating releases/commits in a repo.

[karlgroves]

Thanks for this suggestion. I'm currently looking into how to automate this via a GH action.