.NET-related templates should now include .artifacts

[cmeeren]

According to the .NET 8 Preview 3 announcement, .NET tooling will support a new option to build to a single folder, by default a top-level .artifacts folder in the repo root. This should probably be excluded in all templates relating to .NET. Not sure which those are, and I can't prioritize contributing at the moment, but I wanted to mention it.

[konstrybakov]

Hey, @cmeeren, thank you for bringing this up!

[konstrybakov]

We will consider adding it to our scope, but you are also very welcome to contribute to the change :)

[heysujal]

Hi, @konstrybakov I would like to work on this issue.
I think we need to do changes here
templates/DotnetCore.gitignore
https://github.com/toptal/gitignore/blob/36f6ed1fc974d610bd9fcd1e6fa656bf0ba1f10e/templates/VisualStudio.gitignore#L130