py.typed file / type stubs are missing

[cberner]

Describe the bug
The polygon package does not export its type information to mypy, which causes mypy to fail when used on downstream packages

To Reproduce

1. Download examples/stocks-daily_open_close.py or any other example file
2. mypy stocks-daily_open_close.py
3. Observe the following error:

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

Expected behavior
The type checks should pass

Additional context
I think all that is needed is to add the missing py.typed file to the polygon package