build.ps1 - escape commas for PowerShell

[chris-araman]

Fixes #2395 (comment) from @ray007.

Replaces #2901. This PR targets master instead of cefsharp/75.

Summary:

• Resolves errors of the form:

Could not parse command line parameter 'CefSharp.Wpf.Example'.
An unexpected error occurred | [GitLinkException] GitLink.GitLinkException: Could not parse command line parameter 'CefSharp.Wpf.Example'.
   at GitLink.ArgumentParser.ParseArguments(List`1 commandLineArguments, IProviderManager providerManager)
   at GitLink.Program.Main(String[] args)

Changes:

• Escape commas in GitLink command line for PowerShell

How Has This Been Tested?

• Ran build.ps1. Ensured GitLinkException did not appear.

Screenshots (if appropriate):

• N/A

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Updated documentation

Checklist:

• Tested the code (if applicable)
• Commented my code
• Changed the documentation (if applicable)
• New files have a license disclaimer
• The formatting is consistent with the project (project supports .editorconfig)

[AppVeyorBot]

✅ Build CefSharp 76.1.90-CI3288 completed (commit 096f4fec5d by @chris-araman)