Fix mypy errors in people.py

[tianyizheng02]

Run mypy with --strict flag to fix type hints in people.py

Contributes to #45 by fixing existing type hint errors prior to introducing mypy to the repo.

Before:

> mypy --strict pittapi/people.py                                    
pittapi/people.py:20: error: Skipping analyzing "requests_html": module is installed, but missing library stubs or py.typed marker  [import-untyped]
pittapi/people.py:20: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
pittapi/people.py:44: error: Missing type parameters for generic type "dict"  [type-arg]
pittapi/people.py:47: error: "str" has no attribute "attrs"  [attr-defined]
pittapi/people.py:48: error: "str" has no attribute "text"  [attr-defined]
pittapi/people.py:49: error: "str" has no attribute "text"  [attr-defined]
pittapi/people.py:50: error: "str" has no attribute "text"  [attr-defined]
pittapi/people.py:58: error: "str" has no attribute "text"  [attr-defined]
pittapi/people.py:60: error: "str" has no attribute "text"  [attr-defined]
Found 8 errors in 1 file (checked 1 source file)

After:

mypy --strict pittapi/people.py
pittapi/people.py:20: error: Skipping analyzing "requests_html": module is installed, but missing library stubs or py.typed marker  [import-untyped]
pittapi/people.py:20: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
Found 1 error in 1 file (checked 1 source file)

The sole remaining mypy error is due to requests_html not providing type hints (see https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-library-stubs-or-py-typed-marker). Once we introduce mypy to this repo, we'll need to manually suppress these warnings (e.g., with the --ignore-missing-imports flag).