Upload documents operation doesn't seem to be up to date

[rbufnoir]

The upload-document endpoint doesn't seem to be up to date

When following the documentation and using the uploadDocument method I get an error:
Bad Request\n \n Validation failed ""","code" => 400

If I look the shopping-feed documentation we can see that the endpoint require a multipart/form-data with two specific keys: files and body

Currently the body is badly formatted with for exemple the documents key being mispelled (an 's' is missing)
Furthermore the files key is never set up

In addition, the header is set to 'Content-type: application/json' by default