Same error here.
Ubuntu 20.04.3

bzr dh-make hello 2.10 hello-2.10.tar.gz
brz: ERROR: AttributeError: 'NoneType' object has no attribute 'initialize_on_transport'

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/breezy/plugins/debian/dh_make.py", line 26, in _get_tree
    tree = workingtree.WorkingTree.open(".")
  File "/usr/lib/python3/dist-packages/breezy/workingtree.py", line 201, in open
    control = controldir.ControlDir.open(path, _unsupported=_unsupported)
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 706, in open
    return klass.open_from_transport(t, probers=probers,
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 736, in open_from_transport
    transport, format = _mod_transport.do_catching_redirections(
  File "/usr/lib/python3/dist-packages/breezy/transport/__init__.py", line 1613, in do_catching_redirections
    return action(transport)
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 724, in find_format
    return transport, ControlDirFormat.find_format(transport,
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 1166, in find_format
    raise errors.NotBranchError(path=transport.base)
breezy.errors.NotBranchError: Not a branch: "/home/michael/projetos/empacota_deb/".

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/breezy/plugins/debian/dh_make.py", line 37, in _get_tree
    a_controldir = controldir.ControlDir.open_from_transport(
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 736, in open_from_transport
    transport, format = _mod_transport.do_catching_redirections(
  File "/usr/lib/python3/dist-packages/breezy/transport/__init__.py", line 1613, in do_catching_redirections
    return action(transport)
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 724, in find_format
    return transport, ControlDirFormat.find_format(transport,
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 1166, in find_format
    raise errors.NotBranchError(path=transport.base)
breezy.errors.NotBranchError: Not a branch: "/home/michael/projetos/empacota_deb/hello/".

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/breezy/commands.py", line 1016, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/breezy/commands.py", line 1202, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python3/dist-packages/breezy/commands.py", line 759, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python3/dist-packages/breezy/commands.py", line 784, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/breezy/cleanup.py", line 136, in run_simple
    return _do_with_cleanups(
  File "/usr/lib/python3/dist-packages/breezy/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/breezy/plugins/debian/cmds.py", line 1385, in run
    tree = dh_make.import_upstream(
  File "/usr/lib/python3/dist-packages/breezy/plugins/debian/dh_make.py", line 83, in import_upstream
    tree = _get_tree(package_name)
  File "/usr/lib/python3/dist-packages/breezy/plugins/debian/dh_make.py", line 42, in _get_tree
    branch = create_branch(to_transport.base,
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 660, in create_branch_convenience
    controldir = klass.create(base, format, possible_transports)
  File "/usr/lib/python3/dist-packages/breezy/controldir.py", line 859, in create
    return format.initialize_on_transport(t)
AttributeError: 'NoneType' object has no attribute 'initialize_on_transport'

You can report this problem to Bazaar's developers by running
    apport-bug /var/crash/brz.1000.2021-09-08T22:25.crash
if a bug-reporting window does not automatically appear.