We have no html5lib packaged yet.

--- beautifulsoup4-4.13.5/tox.ini.orig
+++ beautifulsoup4-4.13.5/tox.ini
@@ -11,7 +11,6 @@
 wheel_build_env = .pkg
 description = run the tests with all dependencies installed
 deps = lxml
-     html5lib
      packaging
      soupsieve>=2.6
      pytest>=6