Incompatibility with newer cookiecutter versions

[bollwyvl]

Description

The cookiecutter starter fails to import, probably due to some bad upstream metadata:

Reproduce

• Install jupyter-starters (latest) and cookiecutter (latest)
• Start jupyter lab
• See some errors

terminal output

 Traceback (most recent call last):
      File "~/.venv/lib/python3.9/site-packages/traitlets/traitlets.py", line 537, in get
        value = obj._trait_values[self.name]
    KeyError: '_starters'
    
    During handling of the above exception, another exception occurred:
    
    Traceback (most recent call last):
      File "~/.venv/lib/python3.9/site-packages/notebook/notebookapp.py", line 2030, in init_server_extensions
        func(self)
      File "~/.venv/lib/python3.9/site-packages/jupyter_starters/serverextension.py", line 11, in load_jupyter_server_extension
        nbapp.log.info(f"""<U+1F4A1> starters: {", ".join(manager.starter_names)}""")
      File "~/.venv/lib/python3.9/site-packages/jupyter_starters/manager.py", line 131, in starter_names
        return sorted(dict(self.starters).keys())
      File "~/.venv/lib/python3.9/site-packages/jupyter_starters/manager.py", line 113, in starters
        for name, starter in dict(self._starters).items():
      File "~/.venv/lib/python3.9/site-packages/traitlets/traitlets.py", line 577, in __get__
        return self.get(obj, cls)
      File "~/.venv/lib/python3.9/site-packages/traitlets/traitlets.py", line 540, in get
        default = obj.trait_defaults(self.name)
      File "~/.venv/lib/python3.9/site-packages/traitlets/traitlets.py", line 1580, in trait_defaults
        return self._get_trait_default_generator(names[0])(self)
      File "~/.venv/lib/python3.9/site-packages/traitlets/traitlets.py", line 977, in __call__
        return self.func(*args, **kwargs)
      File "~/.venv/lib/python3.9/site-packages/jupyter_starters/manager.py", line 101, in _default_starters
        starters.update(cookiecutter_starters(self))
      File "~/.venv/lib/python3.9/site-packages/jupyter_starters/py_starters/cookiecutter.py", line 95, in cookiecutter_starters
        *cookiecutter_pantry(),
      File "~/.venv/lib/python3.9/site-packages/jupyter_starters/py_starters/cookiecutter.py", line 119, in cookiecutter_pantry
        str(metadata("cookiecutter")).split("Pantry")[1].split("\n## ")[0].strip()
      File "~/.venv/lib/python3.9/email/message.py", line 135, in __str__
        return self.as_string()
      File "~/.venv/lib/python3.9/email/message.py", line 158, in as_string
        g.flatten(self, unixfrom=unixfrom)
      File "~/.venv/lib/python3.9/email/generator.py", line 116, in flatten
        self._write(msg)
      File "~/.venv/lib/python3.9/email/generator.py", line 199, in _write
        self._write_headers(msg)
      File "~/.venv/lib/python3.9/email/generator.py", line 226, in _write_headers
        self.write(self.policy.fold(h, v))
      File "~/.venv/lib/python3.9/email/_policybase.py", line 326, in fold
        return self._fold(name, value, sanitize=True)
      File "~/.venv/lib/python3.9/email/_policybase.py", line 369, in _fold
        parts.append(h.encode(linesep=self.linesep, maxlinelen=maxlinelen))
      File "~/.venv/lib/python3.9/email/header.py", line 389, in encode
        raise HeaderParseError("header value appears to contain "

• don't see API responses, or any UI (cookiecutter or otherwise)

Expected behavior

• See (empty) cookiecutter list
• See other starters

Context

• trying to write a new starter, don't even want cookiecutter