Update lxml to 6.0.2 on Windows

[twangboy]

What does this PR do?

BlackDuck is detecting libxml2 2.9.12 on Windows. This will update the lxml library which has a newer version of libxml2.

While the version number 2.11.9 looks lower than the required 2.12.10, the lxml maintainers use backpatched versions of the 2.11 branch for their Windows builds to maintain compatibility while fixing these specific CVEs (including CVE-2024-56171).

This also patches some other libraries:

Component	Version in lxml 4.9.1	Version in lxml 6.0.2	Status
libxml2	2.9.12	2.11.9 (Patched)	Fixed (CVE-2024-56171)
zlib	1.2.11	1.2.12 or higher	Fixed (CVE-2018-25032)
libxslt	1.1.34	1.1.39	Updated

From lxml 5.4 Release notes:
5.4.0 (2025-04-22)
Bugs fixed
LP#2107279: Binary wheels use libxml2 2.13.8 and libxslt 1.1.43 to resolve several CVEs. (Binary wheels for Windows continue to use a patched libxml2 2.11.9 and libxslt 1.1.39.) Issue found by Anatoly Katyushin.

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

Commits signed with GPG?

Yes