Update pytest to 3.6.2

[pyup-bot]

This PR updates pytest from 3.6.0 to 3.6.2.

Changelog

3.6.1

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

Bug Fixes
---------

- Fixed a bug where stdout and stderr were logged twice by junitxml when a test
was marked xfail. (`3491
<https://github.com/pytest-dev/pytest/issues/3491>`_)

- Fix ``usefixtures`` mark applyed to unittest tests by correctly instantiating
``FixtureInfo``. (`3498
<https://github.com/pytest-dev/pytest/issues/3498>`_)

- Fix assertion rewriter compatibility with libraries that monkey patch
``file`` objects. (`3503
<https://github.com/pytest-dev/pytest/issues/3503>`_)


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

- Added a section on how to use fixtures as factories to the fixture
documentation. (`3461 <https://github.com/pytest-dev/pytest/issues/3461>`_)


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

- Enable caching for pip/pre-commit in order to reduce build time on
travis/appveyor. (`3502
<https://github.com/pytest-dev/pytest/issues/3502>`_)

- Switch pytest to the src/ layout as we already suggested it for good practice
- now we implement it as well. (`3513
<https://github.com/pytest-dev/pytest/issues/3513>`_)

- Fix if in tests to support 3.7.0b5, where a docstring handling in AST got
reverted. (`3530 <https://github.com/pytest-dev/pytest/issues/3530>`_)

- Remove some python2.5 compatibility code. (`3529
<https://github.com/pytest-dev/pytest/issues/3529>`_)

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

[pyup-bot]

Closing this in favor of #12