[main](backport #42654) docs: Prepare Changelog for 8.17.2

[mergify]

Prepare Changelog for 8.17.2.

Merge once the BC that will be published is decided.

---

This is an automatic backport of pull request #42654 done by Mergify.

[mergify]

Cherry-pick of e182712 has failed:

On branch mergify/bp/main/pr-42654
Your branch is up to date with 'origin/main'.

You are currently cherry-picking commit e18271240.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   CHANGELOG.next.asciidoc

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   CHANGELOG.asciidoc
	both modified:   libbeat/docs/release.asciidoc

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b mergify/bp/main/pr-42654 upstream/mergify/bp/main/pr-42654
git merge upstream/main
git push upstream mergify/bp/main/pr-42654