FFe updating lxml to the 5.2.1 release

[Matthias Klose]

updating lxml to the 5.2.1 release allows us to gid rid off the lxml-html-clean module into a separate package lxmö-html-clean (already in noble), and demote it to universe This module is responsible for almost all CVEs in lxml in the past years.

Changes in 5.2.1 compared to 5.1.0:

5.2.1 (2024-04-02)
==================

Bugs fixed
----------

* LP#2059910: The minimum CPU architecture for the Linux x86 binary wheels was set back to
  "core2", but with SSE 4.2 enabled.

* LP#2059977: ``Element.iterfind("//absolute_path")`` failed with a ``SyntaxError``
  where it should have issued a warning.

* GH#416: The documentation build was using the non-standard ``which`` command.
  Patch by Michał Górny.

5.2.0 (2024-03-30)
==================

Other changes
-------------

* LP#1958539: The ``lxml.html.clean`` implementation suffered from several (only if used)
  security issues in the past and was now extracted into a separate library:

  https://github.com/fedora-python/lxml_html_clean

  Projects that use lxml without "lxml.html.clean" will not notice any difference,
  except that they won't have potentially vulnerable code installed.
  The module is available as an "extra" setuptools dependency "lxml[html_clean]",
  so that Projects that need "lxml.html.clean" will need to switch their requirements
  from "lxml" to "lxml[html_clean]", or install the new library themselves.

* The minimum CPU architecture for the Linux x86 binary wheels was upgraded to
  "sandybridge" (launched 2011), and glibc 2.28 / gcc 12 (manylinux_2_28) wheels were added.

* Built with Cython 3.0.10.

[Matthias Klose (doko)]

this change will need minor changes in two depending packages.

[Graham Inggs (ginggs)]

package split and bugfixes seems fine to me
FFe granted, please go ahead