build/deps: upgrade libxml2 to v2.15.3 (CVE-2026-6732)#30393

tyson-redpanda merged 1 commit intov26.1.xredpanda-data/redpanda:v26.1.xfrom

snyk/cve-2026-6732-libxml2-2.15.3-v26.1.xredpanda-data/redpanda:snyk/cve-2026-6732-libxml2-2.15.3-v26.1.xCopy head branch name to clipboard