Make read_video/write_video support Path from pathlib

[RafailFridman]

🚀 The feature

Currently, read_video method from torchvision.io accepts only a string as its first argument. I suggest making it work also with the Path object from pathlib library.
Like this:

from pathlib import Path
root = Path("videos")
video = read_video(root/"video.mp4", pts_unit="sec")[0]

Currently, it raises ValueError: File object has no read() method, or readable() returned False.

Motivation, pitch

Working with paths as strings is not convenient, and instead, people are using Path from pathlib.

Alternatives

No response

Additional context

No response