Add type stubs about appdirs HOT 2 OPEN

Copying my comment from the PR

Inline typing might be a better fit, but, according to https://www.python.org/dev/peps/pep-0561/, you also would have to add the py.typed marker, which boils down to

• convert the appdirs.py to an appdirs folder with a __init__.py
• comment # type: ... everywhere
• add a py.typed file in there
• make sure that file is bundled within your wheel with some setuptools incantation, i.e

# py_modules=["appdirs"], # no need for this anymore
package_data={"appdirs": ["py.typed"]},
packages=["appdirs"]

see also https://mypy.readthedocs.io/en/latest/installed_packages.html

from appdirs.

Added a pull request with a working type stub file: #75

What's then still missing is including it into setup.py so it's actually downloaded to library users. Apart from that, it should work.

from appdirs.