Docs: note about required Windows Python x86-64 (#4060)

* note about required Windows Python x86-64

Co-authored-by: Arthur Juliani <awjuliani@gmail.com>
Co-authored-by: andrewcoh <54679309+andrewcoh@users.noreply.github.com>

docs/Installation.md

 ### Install **Python 3.6.1** or Higher
 
 We recommend [installing](https://www.python.org/downloads/) Python 3.6 or 3.7.
+If you are using Windows, please install the x86-64 version and not x86.
 If your Python environment doesn't include `pip3`, see these
 [instructions](https://packaging.python.org/guides/installing-using-linux-tools/#installing-pip-setuptools-wheel-with-linux-package-managers)
 on installing it.