* ``Cleaner()`` now validates that only known configuration options can be set.
* LP#1882606: ``Cleaner.clean_html()`` discarded comments and PIs regardless of the
corresponding configuration option, if ``remove_unknown_tags`` was set.
* LP#1880251: Instead of globally overwriting the document loader in libxml2, lxml now
sets it per parser run, which improves the interoperability with other users of libxml2
such as libxmlsec.
* LP#1881960: Fix build in CPython 3.10 by using Cython 0.29.21.
* The setup options "--with-xml2-config" and "--with-xslt-config" were accidentally renamed
to "--xml2-config" and "--xslt-config" in 4.5.1 and are now available again.
OBS-URL: https://build.opensuse.org/package/show/devel:languages:python/python-lxml?expand=0&rev=141
