Fix poetry install

[nphilipp]

Oh noes:

nils@makake:~/src/fedora-infra/duffy (dev)> poetry install
Installing dependencies from lock file

No dependencies to install or update

  ValueError

  Invalid author string. Must be in the format: John Smith <john@example.com>

  at /usr/lib/python3.9/site-packages/poetry/core/packages/package.py:203 in _get_author
      199│ 
      200│         m = AUTHOR_REGEX.match(self._authors[0])
      201│ 
      202│         if m is None:
    → 203│             raise ValueError(
      204│                 "Invalid author string. Must be in the format: "
      205│                 "John Smith <john@example.com>"
      206│             )
      207│ 
nils@makake:~/src/fedora-infra/duffy (dev)>