If your still wondering after 5 years 3 months.
you can't really. unless you spend ages on old cosmos builds but it's just easier getting the 2018 version of cosmos on Visual Studio 2017. in 7-8 years of them coding cosmos, it will be more efficient using the latest build of Visual Studio and Cosmos. But if your used to the old one, then I'm not stopping you from using it. But i'm just suggesting to get the latest one and keep on seeing the latest updates.