MNT Fix github action for deploying userdocs

[GuySartorelli]

Set the branches that activate the action to match the ones used by userhelp according to the userhelp sources json

Also more clearly and accurately identify the specific action (main.yml is hardly specific).

Parent Issue

• The SS4 userhelp as a bunch of "userguide" instead of the actual title doc.silverstripe.org#246

[GuySartorelli]

The scrutinizer failure can be ignored for this PR - we don't use it anymore, and it will be removed as a part of https://github.com/silverstripeltd/product-issues/issues/567

[maxime-rainville]

In theory, if any of the repos are updated the user help should be rebuilt. Would it make more sense to build this on a cron instead?

[GuySartorelli]

In theory, if any of the repos are updated the user help should be rebuilt. Would it make more sense to build this on a cron instead?

maybe? I don't think either approach is really more-or-less valuable than the other.
The current approach means it only gets rebuilt when there are actually changes to make - but it might result in rebuilding the site multiple times in quick succession for weird situations where we find multiple related issues.

A cron approach would mean we rebuild unnecessarily a lot (userdocs are not updated frequently at all) but would mean we don't have to worry about adding and updating these actions anywhere that userdocs sit.

I can see some value in both approaches but I don't think there is enough value in the cron approach to warrant changing it right this very second. Maybe create a new issue for that if you think it's worthwhile?