build(deps): bump lxml

Bumps [lxml](https://github.com/lxml/lxml) from 5.3.0 to 6.1.0.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-5.3.0...lxml-6.1.0)

---
updated-dependencies:
- dependency-name: lxml
  dependency-version: 6.1.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

sdk-platform-java/.cloudbuild/library_generation/scripts/requirements.in

@@ -1 +1 @@
-lxml==5.3.0
+lxml==6.1.0