security/vuxml: document borgbackup < 1.2.5 archive spoofing

Security: b8a52e5a-483d-11ee-971d-3df00e0f9020
Security: CVE-2023-36811
Security: https://github.com/borgbackup/borg/blob/1.2.5-cvedocs/docs/changes.rst#pre-125-archives-spoofing-vulnerability-cve-2023-36811