Skip PowerShell Preview tests on OneBranch (#2228)

v4.2.0: Support PSScriptAnalyzer config in multi-root workspaces (#2213)

v4.1.0: Debugger optimizations and incremental build support!

v4.0.0: Drop support for PowerShell <7.4 and logging overhaul

PowerShell 7.2 LTS and 7.3 are now past end-of-support and are now unsupported.
This is an incompatible API change so we're bumping the major version.
Please update to PowerShell 7.4 LTS going forward.

This release contains a logging overhaul which purposely removes our
dependency on Serilog and should lead to improved stability with
PowerShell 5.1 (by avoiding a major GAC assembly conflict).

v3.21.0: Updates to PSScriptAnalyzer and Call-operator support

v3.20.1: Update third-party notices

v3.20.0: Hotfix for incorrect signing certificate

v3.19.0: Overhauled Terminal Shell Integration!

v3.18.1: Servicing release with updated pipeline!

Bump version to `v3.18.0`