libxml2: update to 2.12.9

Release Notes:
https://gitlab.gnome.org/GNOME/libxml2/-/releases/v2.12.7
https://gitlab.gnome.org/GNOME/libxml2/-/releases/v2.12.8
https://gitlab.gnome.org/GNOME/libxml2/-/releases/v2.12.9

This fixes:
CVE-2024-34459: Fix buffer overread with xmllint --htmlout
CVE-2024-40896: Fix XXE protection in downstream code

Link: https://github.com/openwrt/openwrt/pull/16593
Signed-off-by: Hauke Mehrtens <[email protected]>

package/libs/libxml2/Makefile

@@ -1,12 +1,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libxml2
-PKG_VERSION:=2.12.6
+PKG_VERSION:=2.12.9
 PKG_RELEASE:=1
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@GNOME/libxml2/$(basename $(PKG_VERSION))
-PKG_HASH:=889c593a881a3db5fdd96cc9318c87df34eb648edfc458272ad46fd607353fbb
+PKG_HASH:=59912db536ab56a3996489ea0299768c7bcffe57169f0235e7f962a91f483590
 
 PKG_LICENSE:=MIT
 PKG_LICENSE_FILES:=COPYING