Bump lxml from 5.4.0 to 6.0.0 (#12709)

Bumps [lxml](https://github.com/lxml/lxml) from 5.4.0 to 6.0.0.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-5.4.0...lxml-6.0.0)

---
updated-dependencies:
- dependency-name: lxml
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -27,7 +27,7 @@ html2text==2025.4.15
 humanize==4.12.3
 jira==3.8.0
 PyGithub==1.58.2
-lxml==5.4.0
+lxml==6.0.0
 Markdown==3.8.2
 openpyxl==3.1.5
 Pillow==11.2.1  # required by django-imagekit