Update readme.txt from develop

[jeffpaul]

Description of the Change

This PR cherrypicks just the readme.txt file from develop into trunk to trigger the readme updater action and get the Patchstack FAQ item pushed over to WPORG SVN.

Copilot summary

This pull request makes a minor update to the readme.txt file for the Block Catalog plugin. The most notable change is the addition of instructions for reporting security bugs, directing users to use the Patchstack Vulnerability Disclosure Program.

Documentation updates:

• Added a new section explaining how to report security bugs, including a link to the Patchstack Vulnerability Disclosure Program for coordinated disclosure and CVE assignment.

Other changes:

• Removed the Requires at least: 6.8 line from the plugin header, possibly to defer to other compatibility documentation.

How to test the Change

Changelog Entry

n/a

Credits

Props @jeffpaul.

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.

[jeffpaul]

GHA completed https://github.com/10up/block-catalog/actions/runs/34903292807