[23468] Update 'RELEASE_SUPPORT.md' with EOL of 4.1.x (backport #554)

[mergify]

Description

This PR marks branch 4.1.x as EOL and release v4.1.1 as the latest release of this branch

@Mergifyio backport 4.2.x

Contributor Checklist

• Commit messages follow the project guidelines.

• N/A: Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally

• N/A: New feature has been documented/Current behavior is correctly described in the documentation.

• Applicable backports have been included in the description.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.

---

This is an automatic backport of pull request #554 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 662d9dd has failed:

On branch mergify/bp/4.2.x/pr-554
Your branch is up to date with 'origin/4.2.x'.

You are currently cherry-picking commit 662d9dd.
  (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:   RELEASE_SUPPORT.md

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   .github/pull_request_template.md
	deleted by us:   .github/workflows/nightly-ubuntu-ci.yml

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