Create an integration to monitor annotations (in a group, on a URL) and post them into Slack

[mkdir-washington-edu]

From the Dev sync on 2024-10-17

The initial idea is to use GitHub Actions to do this. We want to be able to monitor annotations made in a group (https://hypothes.is/groups/M8Dqgb9q/hypothesis-eng) or on a site (https://web.hypothes.is/*).

We'll be replacing Integromat as used here: https://hypothes-is.slack.com/archives/C07JHTF5VJT/p1724968435571369
And here: https://hypothes-is.slack.com/archives/C03DXR1BA3B/p1728399213330059

[seanh]

https://github.com/hypothesis/dependabot-alerts <- An example of something that calls the GitHub API (to get our Dependabot security alerts in this case) and posts the results into Slack (example post). For something that posts annotations I'd use the same approach as that repo does.

Alternatively we might add the annotation posting into that same repo, maybe keep all our Slack posting things in one repo (and rename the repo to something more generic).