feat(docs): make reviewers retired option in dependabot's page

[Falcion]

Why:

Dependabot's config (dependabot.yml) from May 20, 2025 requires you to use CODEOWNERS instead of reviewers field. This feature is retired from Dependabot.

Closes #39033

https://github.blog/changelog/2025-04-29-dependabot-reviewers-configuration-option-being-replaced-by-code-owners/

What's being changed (if available, include any code snippets, screenshots, or gifs):

Changed content/code-security/dependabot/working-with-dependabot/dependabot-options-reference.md to include "Important" note about retired functionality.

Check off the following:

• A subject matter expert (SME) has reviewed the technical accuracy of the content in this PR. In most cases, the author can be the SME. Open source contributions may require an SME review from GitHub staff.
• The changes in this PR meet the docs fundamentals that are required for all content.
• All CI checks are passing and the changes look good in the review environment.

[Copilot]

Pull Request Overview

This PR updates the Dependabot documentation to inform users that the reviewers option has been retired in favor of the CODEOWNERS configuration.

• Adds an important callout in the reviewers section
• Provides links to the updated CODEOWNERS documentation and the related blog post

Comments suppressed due to low confidence (1)

content/code-security/dependabot/working-with-dependabot/dependabot-options-reference.md:462

• [nitpick] Consider rephrasing the added note for enhanced clarity. For example, explicitly state that as of Tuesday, May 20, 2025, the reviewers option is deprecated in favor of CODEOWNERS to guide users more directly.

> This feature is retired from `dependabot.yml` and overlaps with [CODEOWNERS](/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners.md) file from Tuesday, May 20, 2025. For more information, read our [blog](https://github.blog/changelog/2025-04-29-dependabot-reviewers-configuration-option-being-replaced-by-code-owners/).

[github-actions]

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Table of review links

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The table shows the files in the content directory that were changed in this pull request. This helps you review your changes on a staging server. Changes to the data directory are not included in this table.

Source	Review	Production	What Changed
code-security/dependabot/working-with-dependabot/dependabot-options-reference.md	fpt ghec ghes@ 3.17 3.16 3.15 3.14 3.13	fpt ghec ghes@ 3.17 3.16 3.15 3.14 3.13

Key: fpt: Free, Pro, Team; ghec: GitHub Enterprise Cloud; ghes: GitHub Enterprise Server

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[Falcion]

I am not sure how to describe this situtation in docs page (and what to do), because:

1. docs must be up-to-date with current state of GitHub's features and at the moment, this feature is legacy (stale) - user may use reviewers field, but not be recommended by the docs to do this.
2. docs must describe every possible field of dependabot.yml, so deleting this block of text is not acceptable.

[Falcion]

PR Checks throw errors with external link to GitHub's official blog:
https://github.com/github/docs/actions/runs/15842617146/job/44657954938?pr=39030

Is there any way to bypass them? I understand that external links are NOT welcome in this docs repo, but I need to reference GitHub's official resources in page, so user could get required context.

[Sharra-writes]

@Falcion Thanks for opening an issue/PR! I'll get writers on the team to review this for adherence to our style guide, and I'll look into the the link check failure. Copilot is telling me that 7 links are failing, and since you haven't updated 7 links, it's possible it's a problem with the test. That particular test has been a bit buggy in the past, so it wouldn't be unprecedented.