[upd] pypi: Bump lxml from 5.1.0 to 5.2.1

Bumps [lxml](https://github.com/lxml/lxml) from 5.1.0 to 5.2.1.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-5.1.0...lxml-5.2.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -3,7 +3,7 @@ babel==2.14.0
 flask-babel==4.0.0
 flask==3.0.2
 jinja2==3.1.3
-lxml==5.1.0
+lxml==5.2.1
 pygments==2.17.2
 python-dateutil==2.9.0.post0
 pyyaml==6.0.1