feature: Dos 4.7

[rnitzan]

Proposed changes

App Protect Dos 4.7

Problem: Added new content for App Protect Dos 4.7

• Add support for Alpine 3.21 and Rocky 9
• Ubuntu 20.04 deprecated

Solution:

Add content to file content/nap-dos/deployment-guide/learn-about-deployment.md

Testing:

Check new content at https://frontdoor-test-docs.nginx.com/previews/docs/814/

Checking

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specific feedback, add them here.

If this PR addresses an issue on GitHub, ensure that you link to it here:

Closes #ISSUE

Checklist

Before merging a pull request, run through this checklist and mark each as complete.

• I have read the contributing guidelines
• I have signed the F5 Contributor License Agreement (CLA)
• I have rebased my branch onto main
• I have ensured my PR is targeting the main branch and pulling from my branch from my own fork
• I have ensured that the commit messages adhere to Conventional Commits
• I have ensured that documentation content adheres to the style guide
• If the change involves potentially sensitive changes¹, I have assessed the possible impact
• If applicable, I have added tests that prove my fix is effective or that my feature works
• I have ensured that existing tests pass after adding my changes
• If applicable, I have updated README.md

Footnotes

1. Potentially sensitive changes include anything involving code, personally identify information (PII), live URLs or significant amounts of new or revised documentation. Please refer to our style guide for guidance about placeholder content. ↩

[github-actions]

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[mjang]

I think there's one typo