[docs] Docs on updating Aqua checksums

[ianlewis]

Renovate can't update CLI tool checksums in aqua-checksums.json. The Aqua docs recommend using autofix.ci but it requires that you give the App write access to your repository code.

While this is perhaps safer than using a PAT on pull_request or pull_request_target, I still don't think I'm ready to give a 3rd party write access to repos.

[ianlewis]

I might want to add a autofix.ci optional workflow job commented out.

[github-actions]

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