Fix Azure Pipelines Ubuntu Image to ubuntu-latest

[X-Guardian]

Pull Request (PR) description

This PR fixes the Ubuntu image used by the Azure Pipelines config to use ubuntu-latest rather than ubuntu 16.04 is this image has been deprecated. It also fixes GitVersion. See https://github.com/dsccommunity/SqlServerDsc/issues/1732 and fixes the HQRM tests to user PowerShell instead of pwsh.

Task list

• [ ] Added an entry to the change log under the Unreleased section of the file CHANGELOG.md. Entry should say what was changed and how that affects users (if applicable), and reference the issue being resolved (if applicable).
• [ ] Resource documentation added/updated in README.md.
• [ ] Resource parameter descriptions added/updated in README.md, schema.mof and comment-based help.
• [ ] Comment-based help added/updated.
• [ ] Localization strings added/updated in all localization files as appropriate.
• [ ] Examples appropriately added/updated.
• [ ] Unit tests added/updated. See DSC Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [ ] New/changed code adheres to DSC Community Style Guidelines.

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This change is 

[codecov[bot]]

Codecov Report

Merging #58 (7b02873) into master (fa1cc05) will not change coverage. The diff coverage is n/a.

@@          Coverage Diff          @@
##           master    #58   +/-   ##
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  Coverage      98%    98%           
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  Files          16     16           
  Lines        2080   2080           
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  Hits         2044   2044           
  Misses         36     36