Enable moving nested projects #559
Description
While I was working with your library i found that it does not allow to update the parent_id of a project through update method. I found that Tableau API allows such change from version 3.1. I really need that functionality in my work so I have looked into the source code and after adding just one if statement to tableauserverclient.server.request_factory file it seemed to work. It's a minor change in code so I can make a pull request if you does not mind it. I really need this as soon as possible, otherwise i will need to make some workaround for the time it's not a feature.