Refactor sports.py to use NamedTuple, fix mypy errors

[tianyizheng02]

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

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

Refactor sports.py to store API output using NamedTuples rather than plain Python dicts. This makes the output more user-friendly, less error-prone, and easier to type-hint.

Before:

mypy --strict pittapi/sports.py            
pittapi/__init__.py:23: error: Skipping analyzing "gevent": module is installed, but missing library stubs or py.typed marker  [import-untyped]
pittapi/__init__.py:23: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
pittapi/sports.py:36: error: Returning Any from function declared to return "str"  [no-any-return]
pittapi/sports.py:39: error: Missing type parameters for generic type "dict"  [type-arg]
pittapi/sports.py:82: error: Returning Any from function declared to return "str"  [no-any-return]
pittapi/sports.py:95: error: Returning Any from function declared to return "str"  [no-any-return]
pittapi/sports.py:98: error: Missing type parameters for generic type "dict"  [type-arg]
pittapi/sports.py:140: error: Returning Any from function declared to return "str"  [no-any-return]
pittapi/sports.py:143: error: Missing type parameters for generic type "dict"  [type-arg]
pittapi/sports.py:144: error: Returning Any from function declared to return "dict[Any, Any]"  [no-any-return]
pittapi/sports.py:147: error: Missing type parameters for generic type "dict"  [type-arg]
pittapi/sports.py:148: error: Returning Any from function declared to return "dict[Any, Any]"  [no-any-return]
Found 11 errors in 2 files (checked 1 source file)

After:

> mypy --strict pittapi/sports.py
pittapi/__init__.py:23: error: Skipping analyzing "gevent": module is installed, but missing library stubs or py.typed marker  [import-untyped]
pittapi/__init__.py:23: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
Found 1 error in 1 file (checked 1 source file)

Like in #193, the remaining missing-imports error will need to be ignored with --ignore-missing-imports because gevent simply doesn't provide any type hints for mypy.