chore: add security.md [PRODSEC-5886]

[cvaidas]

Add SECURITY.md to public repositories. Reach out to ProdSec for any questions.

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Snyk ProdSec

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[snyk-io]

🎉 Snyk checks have passed. No issues have been found so far.

✅ security/snyk check is complete. No issues have been found. (View Details)

✅ license/snyk check is complete. No issues have been found. (View Details)

✅ code/snyk check is complete. No issues have been found. (View Details)