SqlServerDsc: Pester 6 format

Author: johlju

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - SqlServerDsc
   - Replaced inline task `Package_Wiki_Content` with the one now available
     in the module _DscResource.DocGenerator_.
+  - Update tests to Pester 6 format.
 - `Connect-SqlDscDatabaseEngine`
   - Update comment-based help with more examples.
 - SqlSetup