Missing pypi dependency for isodate

[magicbadger]

When using this package as a fresh install from pypi, the module isodate is reported as missing

    from spi.xml import unmarshall
  File "/Users/poor/.pyenv/versions/3.8.0/lib/python3.8/site-packages/spi/xml/__init__.py", line 23, in <module>
    self._target(*self._args, **self._kwargs)
  File "radiovis-server.py", line 45, in launch_provider
    from spi.xml import unmarshall
  File "/Users/poor/.pyenv/versions/3.8.0/lib/python3.8/site-packages/spi/xml/__init__.py", line 23, in <module>
    import isodate

This should be listed as a dependency in the pypi configuration and in the documentation