dir_id: The box.com id for the folder that you'd like to upload to
file: A path to a file stored locally
file_id: the box.com id of the file you'd like to update
Returns
The httr() object returned by the api call
Details
The box.com api requires different API calls to upload a new file, and to upload a new version of a file which already exists (incrementing the version number).
box_upload_new make the API call to upload a new file. box_update_file makes the API call to update an existing file.