update: libxml2

[dongsupark]

Name: libxml2
CVEs: CVE-2024-40896
CVSSs: 9.1
Action Needed: update to >= 2.12.9

Summary: In libxml2 2.11 before 2.11.9, 2.12 before 2.12.9, and 2.13 before 2.13.3, the SAX parser can produce events for external entities even if custom SAX handlers try to override entity content (by setting "checked"). This makes classic XXE attacks possible.

refmap.gentoo: https://bugs.gentoo.org/943198

[dongsupark]

Done in flatcar/scripts#2580.