Improved the example for artifact usage

I think the current example is very confusing. It's not clear if the path in dest is a directory where the actual file will be placed or if it's the exact path of the file within the tar.

Furthermore, I added an example to show the "put the whole directory in the tar" feature which was something I missed so much in 2.1. I was very happy to find out in the code that it was possible now.