[BUG]: Security link goes nowhere

[lgritz]

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What version (or hash if on master) of pybind11 are you using?

master

Problem description

https://github.com/pybind/pybind11/security/policy

If you click the link to disclose a security advisory, it gets a 404

Reproducible example code

Is this a regression? Put the last known working version here if it is.

Not a regression