important section is mandatory when setup.cfg exists

[sk-]

If you already have a setup.cfg file in your project, then it is mandatory to have the important section in it.

Without it the command fails with:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/configparser.py", line 846, in items
    d.update(self._sections[section])
KeyError: 'important'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/user/.virtualenvs/venv/bin/important", line 7, in <module>
    from important.__main__ import check
  File "/Users/user/.virtualenvs/venv/lib/python3.6/site-packages/important/__main__.py", line 37, in <module>
    dict(map(split, CONFIG.items('important')))
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/configparser.py", line 849, in items
    raise NoSectionError(section)
configparser.NoSectionError: No section: 'important'