Delete any directories listed in the RECORD file (#394)
## Summary
It looks like, when you install `pip`, it includes a bunch of
`__pycache__` directories in the RECORD file (although these directories
don't exist until you run `pip`). Our uninstaller assumed that the
RECORD file only contained _files_.
Closes https://github.com/astral-sh/puffin/issues/389.
