Upload python packages to PyPI

**Role Variables**

.. zuul:rolevar:: pypi_info

   Complex argument which contains the information about the PyPI
   server as well as the authentication information needed. It is
   expected that this argument comes from a `Secret`.

  .. zuul:rolevar:: api_token
     :default: None

     PyPi API token to use for upload.  If specified, ``username`` and
     ``password`` should be empty.

  .. zuul:rolevar:: username

     Username to use to log in to PyPI.  `Note` PyPi reccommends using
     two-factor auth and generating an API token for uploading.

  .. zuul:rolevar:: password

     Password to use to log in to PyPI.

  .. zuul:rolevar:: repository
     :default: pypi

     Name of the repository to upload to.

  .. zuul:rolevar:: repository_url
     :default: The built-in twine default for the production pypi.org service.

     URL of the PyPI repostory.

.. zuul:rolevar:: pypi_path
   :default: src/{{ zuul.project.canonical_name }}/dist

   Path containing artifacts to upload.

.. zuul:rolevar:: pypi_twine_executable
   :default: twine

   Path to twine executable.

.. zuul:rolevar:: pypi_twine_skip_existing
   :default: false

   Skip uploading any file which already exists, rather than failing.

.. zuul:rolevar:: pypi_register_first
  :default: false

  Whether the role should register the package before uploading it. This may
  be required when uploading for the first time to a devPI instance.