Update .gitignore to include default virtual environment
Update .gitignore to include default virtual environment

The default virtual environment installed when users run the installation script is called `augur_venv`. This was somehow removed from the `.gitignore`, meaning that we are now seeing the virtual environment files being checked in version control. This causes problems for other users, as the virtual environment is then unable to resolve on any machine other the person who checked them in first.
OSSHealth/ghdata,OSSHealth/ghdata,OSSHealth/ghdata