Update DB upgrade links in table

What does this MR do?

Adds entry for bumped PostgreSQL versions in GitLab v16.6.1 due to CVE-2023-39417

The original change was already covered by another MR; however, an issue with the links was discovered and fixed here. MR title updated to align with this new purpose.

Related issues

I assume there is one for the upgrade, but it is probably internal as it was security relevant.

Author's checklist

• Optional. Consider taking the GitLab Technical Writing Fundamentals course.
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Reviewer's checklist

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