Use a uniq ID for the S3 direct upload key

self.key = "{}/{}".format(s3_info["baseKey"].rstrip("/"), self.blob.name)

# file: test-s3.py
from nuxeo.client import Nuxeo
from nuxeo.models import FileBlob


host = "SERVER"
auth = ("USER", "PWD")
server = Nuxeo(host=host, auth=auth)

batch = server.uploads.batch(handler="s3")
blob = FileBlob(".../fah-installer_7.6.13_x86_64 (1).mpkg.zip")
batch.upload(blob)
batch.complete()

Traceback (most recent call last):
  File "nuxeo/client.py", line 282, in request
    resp.raise_for_status()
  File ".../requests/models.py", line 941, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 400 Client Error:  for url: SERVER/nuxeo/api/v1/upload/batchId-9008aa8c-1af8-4d15-a67d-cb6830bbd341/0/complete

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "test-s3.py", line 12, in <module>
    batch.complete()
  File "nuxeo/models.py", line 230, in complete
    return self.service.complete(self, **kwargs)
  File "nuxeo/uploads.py", line 305, in complete
    return self.client.request("POST", endpoint, data=params, **kwargs)
  File "nuxeo/client.py", line 285, in request
    raise self._handle_error(exc)
nuxeo.exceptions.HTTPError: HTTPError(400), error: 'java.lang.IllegalArgumentException: Invalid key: fah-installer_7.6.13_x86_64 (1).mpkg.zip', server trace: None

from uuid import uuid4

self.key = "{}/{}".format(s3_info["baseKey"].rstrip("/"), uuid4())