-O flag does not respect S3 URIs

[WillNilges]

Current Situation

I have a Django project with dbbackup backed by S3. This is configured in my settings.py. When I am trying to do one-off backups, I want to run the command python manage.py dbbackup -O s3://meshdb-backups/dev/. However, I am getting an exception when I try to run that command:

INFO:dbbackup.command:Writing file to s3://meshdb-data-backups/meshdb-backups/dev/
ERROR:dbbackup:FileNotFoundError: [Errno 2] No such file or directory: 's3://meshdb-data-backups/meshdb-backups/dev/'
  File "/usr/local/lib/python3.11/site-packages/dbbackup/utils.py", line 116, in wrapper
    func(*args, **kwargs)
  File "/usr/local/lib/python3.11/site-packages/dbbackup/management/commands/dbbackup.py", line 100, in handle
    self._save_new_backup(database)
  File "/usr/local/lib/python3.11/site-packages/dbbackup/management/commands/dbbackup.py", line 142, in _save_new_backup
    self.write_local_file(outputfile, self.path)
  File "/usr/local/lib/python3.11/site-packages/dbbackup/management/commands/_base.py", line 108, in write_local_file
    with open(path, "wb") as fd:
         ^^^^^^^^^^^^^^^^
  File "/datadog-lib/ddtrace_pkgs/site-packages-ddtrace-py3.11-manylinux2014/ddtrace/appsec/_common_module_patches.py", line 85, in wrapped_open_CFDDB7ABBA9081B6
    raise e.with_traceback(
  File "/usr/local/lib/python3.11/site-packages/dbbackup/management/commands/_base.py", line 108, in write_local_file
    with open(path, "wb") as fd:
         ^^^^^^^^^^^^^^^^

Traceback (most recent call last):
  File "/opt/meshdb/manage.py", line 26, in <module>
    main()
  File "/opt/meshdb/manage.py", line 22, in main
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.11/site-packages/django/core/management/__init__.py", line 442, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.11/site-packages/django/core/management/__init__.py", line 436, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.11/site-packages/django/core/management/base.py", line 412, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.11/site-packages/django/core/management/base.py", line 458, in execute
    output = self.handle(*args, **options)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/dbbackup/utils.py", line 116, in wrapper
    func(*args, **kwargs)
  File "/usr/local/lib/python3.11/site-packages/dbbackup/management/commands/dbbackup.py", line 100, in handle
    self._save_new_backup(database)
  File "/usr/local/lib/python3.11/site-packages/dbbackup/management/commands/dbbackup.py", line 142, in _save_new_backup
    self.write_local_file(outputfile, self.path)
  File "/usr/local/lib/python3.11/site-packages/dbbackup/management/commands/_base.py", line 108, in write_local_file
    with open(path, "wb") as fd:
         ^^^^^^^^^^^^^^^^
  File "/datadog-lib/ddtrace_pkgs/site-packages-ddtrace-py3.11-manylinux2014/ddtrace/appsec/_common_module_patches.py", line 85, in wrapped_open_CFDDB7ABBA9081B6
    raise e.with_traceback(
  File "/usr/local/lib/python3.11/site-packages/dbbackup/management/commands/_base.py", line 108, in write_local_file
    with open(path, "wb") as fd:
         ^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: 's3://meshdb-data-backups/meshdb-backups/dev/'

Proposed Actions

Ensure that the -O flag understands S3.

System Information

DBBackup version: 3ccac96

Django: "django==4.2.*",

Python: python:3.11-bookworm