PR Summary

Also update the minor version of Pester v4 being used.

PR Context

Pester v5 will release in the next days and will be a big breaking change that will take a while to have a PR for it. This should keep the builds green.
https://twitter.com/nohwnd/status/1246497254938206210

PR Checklist

• PR has a meaningful title
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• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge and is not Work in Progress.
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• Breaking changes
  • None
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  • Experimental feature(s) needed
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• User-facing changes
  • Not Applicable
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  • Documentation needed
    • Issue filed:
• Testing - New and feature
  • N/A or can only be tested interactively
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  • Make sure you've added a new test if existing tests do not effectively test the code changed
• Tooling
  • I have considered the user experience from a tooling perspective and don't believe tooling will be impacted.
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    • Impact on PowerShell Editor Services which is used in the PowerShell extension for VSCode (which runs in a different PS Host).
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