Improvements to the documentation for installing to a virtualenv

[nisc586]

• roocs-utils version: ?
• Python version: 3.10
• Operating System: Windows

Description

Hi,
The way to install nappy to a virtualenv as it is described in the ReadMe does not work on Windows.
It also looks a bit outdated, so I would like to change it to a version that uses pip.

I also noticed, that the setup fails if the pypandoc package is installed. Apparently pypandocs convert-function has been renamed to convert_file.

What I Did

I prepared a pull request where I updated the ReadMe. I also renamed the convert function in setup.py.