Create LTS 2.492.3 changelog and upgrade guide

[kmartens27]

This PR is to create the 2.492.3 changelog and upgrade guide, based on jenkinsci/jenkins#10417

There are no entries for the upgrade guide so it follows the pattern of previous editions that have no entries.

[gounthar]

Thank you, Kevin! 🙏

[MarkEWaite]

Thanks!

[gounthar]

This is my first time as a release lead here! 😊

I'm wondering why I can't see the changelog for version 2.492.3 even though this PR has been merged. Could anyone shed some light on this? 🤔
Will it be automatically published once the release build finishes, or do I have something to do?

Thanks!

[kmartens27]

Hi @gounthar, that is correct. The changelog has been merged and in addition to that, the security team will be updating their own version of the changelog with the security release information. Once everything is published/released on their side, the changelog will appear as it would normally.

[gounthar]

Thanks a lot for the explanation, Kevin. 🙏

[kmartens27]

Of course! The weekly changelog is usually merged only after the build is ready/available so it doesn't face the same issues. The LTS changelog is typically completed and merged at least a handful of days prior to the actual release.