Howto: Installing dependencies of regsecrets in a venv

In case you'd like to avoid installing python packages globally. Quite hacky, but it works for me:

```shell
cd MemProcFS
python3 -m venv .venv
. .venv/bin/activate
pip install pypykatz aiowinreg
sitepkgs=$(python3 -c "import sysconfig; print(sysconfig.get_path('purelib'))")
ln -s $sitepkgs pylib
```
