dep: bump libxml2 to 2.13.7

https://gitlab.gnome.org/GNOME/libxml2/-/releases/v2.13.7

This is a bugfix release

(cherry picked from commit f510117)

Author: flavorjones

dependencies.yml

@@ -1,8 +1,8 @@
 ---
 libxml2:
-  version: "2.13.6"
-  sha256: "f453480307524968f7a04ec65e64f2a83a825973bcd260a2e7691be82ae70c96"
-  # sha-256 hash provided in https://download.gnome.org/sources/libxml2/2.13/libxml2-2.13.6.sha256sum
+  version: "2.13.7"
+  sha256: "14796d24402108e99d8de4e974d539bed62e23af8c4233317274ce073ceff93b"
+  # sha-256 hash provided in https://download.gnome.org/sources/libxml2/2.13/libxml2-2.13.7.sha256sum
 
 libxslt:
   version: "1.1.43"