fixed: type hinting issue in download_parallel_corpora.py

[lavaman131]

Minor issue with the type hint list[str] for Python < 3.9 so I replaced list with typing.List in:

def download_Flores202(directory, eval_directions: List[str]):
    ...

https://stackoverflow.com/questions/63460126/typeerror-type-object-is-not-subscriptable-in-a-function-signature

[gordicaleksa]

thank you!