TypeError: Unicode-objects must be encoded before hashing

[ukanga]

Happens when publishing with form builder a text XLSForm under python 3 environment and using boto3 with S3 as the storage backend.

https://sentry.onalabs.org/ona/ona-api-stage/issues/72466/

TypeError: Unicode-objects must be encoded before hashing
(16 additional frame(s) were not displayed)
...
  File "onadata/libs/utils/logger_tools.py", line 479, in publish_form
    return callback()
  File "onadata/apps/api/tools.py", line 369, in set_form
    return form.publish(project.organization, created_by=request.user)
  File "onadata/apps/main/forms.py", line 360, in publish
    ContentFile(csv_data))

TypeError: Unicode-objects must be encoded before hashing

Aha! Link: https://ona.aha.io/features/PROD-261