Automated testing of PSGallery upload

[lupino3]

Azure Artifacts can be used as a PowerShell repository (it's NuGet after all): https://docs.microsoft.com/en-us/azure/devops/artifacts/tutorials/private-powershell-library?view=azure-devops

It would be nice to automatically test:

• upload to PSGallery;
• fetch from PSGallery;
• do some basic tests with the module.