suggestion to add pathlib.Path exmple for file upload to docs

We noticed in a workshop that this works when uploading a file:

resource.upload("My file as it would appear in Coscine.txt", Path('path/to/file.txt').read_text(), metadata)

We can add this as another one-line way to upload data using pathlib.Path files.

@romin.benfer what do you think? I'm happy to make the edit, but I haven't tried anything similar out with other types of files.