Update PowerShell SDK to 7.2.19

[andystaples]

Update PowerShell SDK to latest

• Update PowerShell SDK to 7.2.19
• Update .NET SDK to 6.0.421

resolves #1054

Pull request checklist

• [x] My changes do not require documentation changes
  • [ ] Otherwise: Documentation issue linked to PR
• [ ] My changes should not be added to the release notes for the next release
  • [ ] Otherwise: I've added my notes to release_notes.md
• [x] My changes do not need to be backported to a previous version
  • [ ] Otherwise: Backport tracked by issue/PR #issue_or_pr
• [x] I have added all required tests (Unit tests, E2E tests)