Add instructions for security reports

[curious-rabbit]

There is currently no way to report an issue confidentially. The openly option to reach the developers is through a public bug report, which is not idea for reporting vulnerabilities. Please consider enabling githubs security report form.

[llyyr]

You can email one or more maintainers with the report

[curious-rabbit]

And where do I find the email? There should be official instructions for the project about who to contact.

[kasper93]

See #17642, it's not final wording, but you can use the security reporting feature in github or contact our security team listed there directly, emails are in profiles on github.

[curious-rabbit]

Thank you