Consider using "Sequence" instead of "List"

Feature request

Hi, please consider using Sequence type annotation instead of List in function arguments such as in Dataset.from_parquet(). It leads to type checking errors, see below.

How to reproduce

list_of_filenames = ["foo.parquet", "bar.parquet"]
ds = Dataset.from_parquet(list_of_filenames)

Expected mypy output:

Success: no issues found

Actual mypy output:

test.py:19: error: Argument 1 to "from_parquet" of "Dataset" has incompatible type "List[str]"; expected "Union[Union[str, bytes, PathLike[Any]], List[Union[str, bytes, PathLike[Any]]]]"  [arg-type]
test.py:19: note: "List" is invariant -- see https://mypy.readthedocs.io/en/stable/common_issues.html#variance
test.py:19: note: Consider using "Sequence" instead, which is covariant

Env: mypy 0.991, Python 3.10.0, datasets 2.7.1