Extract and supply file mimetype for DataFile upload

[JR-1991]

Overview

In issue #171, it was reported that replacing data files was not working due to an incorrect mime-type being submitted. Specifically, when trying to replace a docx file, the pyDataverse library was supplying text/plain as the mime-type, which was causing the issue.

It appears that this error originated from Python's request library, which was failing to supply the correct mime-type upon upload and was falling back to text/plain. As a result, Dataverse rejected the replacement due to a different mime type being supplied than what already existed.

In order to resolve the issue, the proposed solution involves extending the post_request and determining the mime-types before initiating a POST request. For this purpose, the implementation employs Python's mimetypes library to predict the mimetype. Subsequently, the identified mime-type is passed to the request.post method. If the mime-type cannot be guessed, the method returns to the current implementation.

ToDos

• Mimetype detection before POST request
• Add test case for file replacement

Closes

Fixes #171