Support switching between virtualenvs

[giahung24]

Hello, Thank you for this nice extension! It'd better if you can add a config/setting that allows user to choose which pip to manage. Imagine we have many virtualenvs (different python paths), this option will allow user switching between his environments and easily manage pip packages from each env.

[angelhdzdev]

I came from Node Package Manager and immediately noticed that all the listed packages are the global ones, not the current venv ones. So +1 for this feature! Thanks.