Deps: Bump the python-packages group with 3 updates

Bumps the python-packages group with 3 updates: [lxml](https://github.com/lxml/lxml), [pontos](https://github.com/greenbone/pontos) and [ruff](https://github.com/astral-sh/ruff).


Updates `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)

Updates `pontos` from 25.4.0 to 25.6.0
- [Release notes](https://github.com/greenbone/pontos/releases)
- [Commits](greenbone/pontos@v25.4.0...v25.6.0)

Updates `ruff` from 0.12.0 to 0.12.1
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.12.0...0.12.1)

---
updated-dependencies:
- dependency-name: lxml
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: python-packages
- dependency-name: pontos
  dependency-version: 25.6.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: python-packages
- dependency-name: ruff
  dependency-version: 0.12.1
  dependency-type: indirect
  update-type: version-update:semver-patch
  dependency-group: python-packages
...

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Author: dependabot[bot]