Not compatible with libxml2 2.15

[fabien-michel]

Trying to install inscriptis 2.7.0 on container with libxml2 2.15 (which is the case of Debian Trixie) is failing because
insciptis 2.7.0 require lxml < 6 and the fixes for libxml2 2.15 where made in lxml 6.0.1 and 6.0.2 (https://github.com/lxml/lxml/releases/tag/lxml-6.0.2)

[AlbertWeichselbraun]

Thank you for reporting this issue (and providing a fix :). I will release 2.7.1 shortly, so that the version with the fixed dependencies can be installed via PyPI as well.