Update pytest to 3.6.4

[pyup-bot]

This PR updates pytest from 3.6.2 to 3.6.4.

Changelog

3.6.4

=========================

Bug Fixes
---------

- Invoke pytest using ``-mpytest`` so ``sys.path`` does not get polluted by packages installed in ``site-packages``. (`742 <https://github.com/pytest-dev/pytest/issues/742>`_)


Improved Documentation
----------------------

- Use ``smtp_connection`` instead of ``smtp`` in fixtures documentation to avoid possible confusion. (`3592 <https://github.com/pytest-dev/pytest/issues/3592>`_)


Trivial/Internal Changes
------------------------

- Remove obsolete ``__future__`` imports. (`2319 <https://github.com/pytest-dev/pytest/issues/2319>`_)

- Add CITATION to provide information on how to formally cite pytest. (`3402 <https://github.com/pytest-dev/pytest/issues/3402>`_)

- Replace broken type annotations with type comments. (`3635 <https://github.com/pytest-dev/pytest/issues/3635>`_)

- Pin ``pluggy`` to ``<0.8``. (`3727 <https://github.com/pytest-dev/pytest/issues/3727>`_)

3.6.3

=========================

Bug Fixes
---------

- Fix ``ImportWarning`` triggered by explicit relative imports in
assertion-rewritten package modules. (`3061
<https://github.com/pytest-dev/pytest/issues/3061>`_)

- Fix error in ``pytest.approx`` when dealing with 0-dimension numpy
arrays. (`3593 <https://github.com/pytest-dev/pytest/issues/3593>`_)

- No longer raise ``ValueError`` when using the ``get_marker`` API. (`3605
<https://github.com/pytest-dev/pytest/issues/3605>`_)

- Fix problem where log messages with non-ascii characters would not
appear in the output log file.
(`3630 <https://github.com/pytest-dev/pytest/issues/3630>`_)

- No longer raise ``AttributeError`` when legacy marks can't be stored in
functions. (`3631 <https://github.com/pytest-dev/pytest/issues/3631>`_)


Improved Documentation
----------------------

- The description above the example for ``pytest.mark.skipif`` now better
matches the code. (`3611
<https://github.com/pytest-dev/pytest/issues/3611>`_)


Trivial/Internal Changes
------------------------

- Internal refactoring: removed unused ``CallSpec2tox ._globalid_args``
attribute and ``metafunc`` parameter from ``CallSpec2.copy()``. (`3598
<https://github.com/pytest-dev/pytest/issues/3598>`_)

- Silence usage of ``reduce`` warning in Python 2 (`3609
<https://github.com/pytest-dev/pytest/issues/3609>`_)

- Fix usage of ``attr.ib`` deprecated ``convert`` parameter. (`3653
<https://github.com/pytest-dev/pytest/issues/3653>`_)

Links

• PyPI: https://pypi.org/project/pytest
• Changelog: https://pyup.io/changelogs/pytest/
• Repo: https://github.com/pytest-dev/pytest/issues
• Homepage: http://pytest.org