chore(deps): update lxml requirement from <5 to <6

Updates the requirements on [lxml](https://github.com/lxml/lxml) to permit the latest version.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-0.5.1...lxml-5.0.0)

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

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

requirements.txt

@@ -1,5 +1,5 @@
 ansible-core>=2.15,<2.15.5
 graphviz>=0.18,<1
 colour<1
-lxml<5
+lxml<6
 svg.path<7