Here is a potentially quick fix by adding to the custom footer as follows:

<p class="text-small text-grey-dk-100 mb-0">
    Copyright &copy; 2017-{{ site.time | date: '%Y' }} {{ site.footer_content }}</a>"
</p>

...while retaining the _config.yml footer_content flag (with just a small change):

footer_content: "Patrick Marsceill. Distributed by an <a href=\"https://github.com/just-the-docs/just-the-docs/tree/main/LICENSE.txt\">MIT license.</a> <a href=\"https://www.netlify.com/\">This site is powered by Netlify.</a>"

And adding the following lines to the deploy.yml and CI.yml workflows:

on:
  push:
    branches: ["main"]
  schedule:
    - cron: '0 0 1 1 *'  # Run at 12:00 AM 01/01 every year to update copyright date

This will make it so that the website is rebuilt on the beginning of each year to update copyright!

Is it possible to link the pull request (#1384) I opened to this issue (I think a maintainer needs to do it)

Thanks for submitting an issue @392781! There's actually a reason that we haven't updated this just yet - I need to figure out with Patrick exactly how he wants the copyright for this to work (he transitioned this into this GitHub organization and stepped down as a maintainer in 2020). I've elected to not update the copyright footer until we've sorted that out. This is a good reminder for me to check in with him though!

Separately - I don't think a cron job (or even a custom footer) is necessary for this feature - it's infrequent enough that we can just update it manually, or use a "wildcard" of sorts (e.g. 2017-* or 2020-*).

Do any other maintainers want to chime in? I'll send Patrick an email once the work day is over for me!

IMO, it's simple enough future-proofing that doesn't have significant impact on development while keeping the website looking professional and up to date. Its pretty common to see out of date copyrights for manually updated websites... it's small enough to slip through the cracks.

That said, I didn't realize there was some historical things to take care of. If anything, these changes may be useful for someone downstream using just-the-docs :^) I mainly created the pull because it's an elegant solution that we're using for our documentation.