Add virtual env information to Oh my Posh prompt

venv.txt

Past the following in the "segments" section of the theme's JSON file:
{
    "background": "#FFDE57",
    "foreground": "#111111",
    "powerline_symbol": "\ue0b0",
    "properties": {
        "display_mode": "environment",
        "fetch_virtual_env": true,
        "home_enabled": true
    },
    "style": "powerline",
    "template": " \ue235 {{ if .Venv }}({{ .Venv }}){{ end }} ",
    "type": "python"
}