[DO NOT MERGE] Pester 6.0.0 release candidate update

[nohwnd]

Hi — Pester 6.0.0 is almost ready, and before I release it I'm trying it out
against real-world Pester v5 test suites.

This PR updates Pester to the 6.0.0 release candidate and makes the changes
needed for your tests to run on it. I opened it to learn two things:

• whether migrating from v5 to v6 is straightforward, and
• where v6 breaks or behaves differently, so I can fix those things before the
  final release instead of after.

You don't need to merge this, and I'd suggest you don't — it's only meant to
show what a v6 update would involve and to give me feedback. Please leave it
open, though: if more release candidates come out I'll push those updates here
too, and I'll close it myself afterwards.

This PR was co-authored by GitHub Copilot. If you'd rather not receive
AI-assisted PRs, just close it and I won't open one for the next release.

Thanks for the CI time this run used, and for maintaining a suite I could test
against.

— Jakub & Copilot

[sonarqubecloud]

Quality Gate passed

Issues
37 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[nohwnd]

Pester 6.0.0 is now released 🎉 — https://github.com/pester/Pester/releases/tag/6.0.0

Thanks for letting me pilot the release candidates against TfsCmdlets. Closing this throwaway pilot PR now that 6.0.0 is out.

I couldn't get a clean Pester signal here: the suite fails in _TestSetup.ps1's BeforeAll because a fork run has no TFSCMDLETS_ACCESS_TOKEN / TFSCMDLETS_COLLECTION_URL secrets, so all ~139 tests error before exercising anything Pester-specific. That's an environment/secrets limitation on a fork PR, not a Pester issue (Pester 6 correctly surfaces the BeforeAll throw as a failure).

If you'd like to try 6.0.0 with your own secrets, the migration notes are here: https://pester.dev/docs/migrations/v5-to-v6 — happy to help.

— Jakub & Copilot