Support multiple `IO` types

Overview

This pull request introduces the possibility of passing other IO objects, such as BytesIO or StringIO, alongside local files.

Example

from dvuploader import File, DVUploader
from io import BytesIO

handler = BytesIO(b"some file data")
file = File(
    filepath="somefile.txt",
    handler=handler,
)

uploader = DVUploader(files=[file])
uploader.upload(
    persistent_id="<persistent_id>",
    api_token="<api_token>",
    dataverse_url="<dataverse_url>",
)

gdcc / python-dvuploader

Support multiple `IO` types #12