Deploy with github actions so we can use jekyll 4

[hackartisan]

see

• Support for Jekyll 4.0 github/pages-gem#651
• https://jekyllrb.com/docs/continuous-integration/github-actions/

[hackartisan]

I forked the repo so I can give this a test run. Steps I've taken so far

• Turn off publishing by going to settings > pages > switch source from "deploy from a branch" to "github actions"
• a little box with jekyll in it will appear. click "configure"
• It generates a yml file in /.github/workflows/jekyll.yml -- click "commit changes"

after that i tried various things, all in the commit history. putting this down for now in favor of other priorities.

[hackartisan]

Here are the commits that make this work. We should be able to make a PR from the hackartisan/test-gh-actions branch to this repo, and update the configuration under settings > pages > source.

https://github.com/hackartisan/dls-handbook/pulls?q=is%3Apr+is%3Aclosed