Bump peaceiris/actions-gh-pages to 3.9.0.

[felixfontein]

Right now the shared workflow triggers a warning (Node.js 12 actions are deprecated. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/. Please update the following actions to use Node.js 16: peaceiris/actions-gh-pages@068dc23d9710f1ba62e86896f84735d869951305). Let's upgrade the action to 3.9.0 which fixes that (https://github.com/peaceiris/actions-gh-pages/blob/v3.9.0/CHANGELOG.md#feat).

[briantist]

Thank you for this!

I still need to look into using dependabot for this type of thing, some more info in

• #10

I think lowlydba.sqlserver is already doing that I just haven't had a chance to try it myself:

• https://github.com/lowlydba/lowlydba.sqlserver/pulls?q=is%3Apr+is%3Aclosed+author%3Aapp%2Fdependabot

[felixfontein]

I'm also using dependabot for workflows in the antsibullbot* repositories. Adding it is pretty simple, simply add a file like https://github.com/ansible-community/antsibull/blob/main/.github/dependabot.yml into this repository's .github directory. Maybe we should try this out, just to see what happens.