Update pytest to 3.0.3

[pyup-bot]

There's a new version of pytest available.
You are currently using 3.0.2. I have updated it to 3.0.3

Changelog

3.0.3

• The ids argument to parametrize again accepts unicode strings
  in Python 2 (1905).
  Thanks philpep for the report and nicoddemus_ for the PR.
• Assertions are now being rewritten for plugins in development mode
  (pip install -e) (1934).
  Thanks nicoddemus for the PR.
• Fix pkg_resources import error in Jython projects (1853).
  Thanks raquel-ucl_ for the PR.
• Got rid of AttributeError: 'Module' object has no attribute '_obj' exception
  in Python 3 (1944).
  Thanks axil for the PR.
• Explain a bad scope value passed to fixture declarations or
  a MetaFunc.parametrize() call. Thanks tgoodlet_ for the PR.
• This version includes pluggy-0.4.0, which correctly handles
  VersionConflict errors in plugins (704).
  Thanks nicoddemus for the PR.

.. _philpep: https://github.com/philpep
.. _raquel-ucl: https://github.com/raquel-ucl
.. _axil: https://github.com/axil
.. _tgoodlet: https://github.com/tgoodlet

.. _1905: pytest-dev/pytest#1905
.. _1934: pytest-dev/pytest#1934
.. _1944: pytest-dev/pytest#1944
.. _704: pytest-dev/pytest#704

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖