Added py.typed metadata file

[jamesbraza]

Adds a missing py.typed file to satisfy mypy for client repos.

With this Python file:

# a.py

import paperscraper

Running pip install git+https://github.com/blackadad/paper-scraper mypy==1.8.0 then mypy a.py:

a.py:3: error: Skipping analyzing "paperscraper": module is installed, but missing library stubs or py.typed marker  [import-untyped]
a.py:3: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
Found 1 error in 1 file (checked 1 source file)

Now running pip install git+https://github.com/jamesbraza/paper-scraper@py-typed mypy==1.8.0 then mypy a.py:

/Users/user/.pyenv/versions/3.11.8/lib/python3.11/site-packages/pypdf/_crypt_providers/_pycryptodome.py:30: error: Cannot find implementation or library stub for module named "Crypto"  [import-not-found]
/Users/user/.pyenv/versions/3.11.8/lib/python3.11/site-packages/pypdf/_crypt_providers/_pycryptodome.py:31: error: Cannot find implementation or library stub for module named "Crypto.Cipher.AES"  [import-not-found]
/Users/user/.pyenv/versions/3.11.8/lib/python3.11/site-packages/pypdf/_crypt_providers/_pycryptodome.py:31: error: Cannot find implementation or library stub for module named "Crypto.Cipher.ARC4"  [import-not-found]
...

(That means it works, just I don't have my mypy config properly dialed in)