fix(deps): update dependency wagtail to v6 [security]

Author: renovate[bot]

pyproject.toml

@@ -58,7 +58,7 @@ dependencies = [
     "user-agents==2.2.0",
     "user-util==2.0.0",
     "uwsgi==2.0.31",
-    "wagtail==5.2.8",
+    "wagtail==6.3.8",
     "wagtail-metadata==5.0.0",
     "xmltodict>=1.0.0,<2",
     "zeep==4.3.2",