Update pytest to 3.6.0

[pyup-bot]

This PR updates pytest from 3.5.1 to 3.6.0.

Changelog

3.6.0

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

Features
--------

- Revamp the internals of the ``pytest.mark`` implementation with correct per
node handling which fixes a number of long standing bugs caused by the old
design. This introduces new ``Node.iter_markers(name)`` and
``Node.get_closest_mark(name)`` APIs. Users are **strongly encouraged** to
read the `reasons for the revamp in the docs
<https://docs.pytest.org/en/latest/mark.htmlmarker-revamp-and-iteration>`_,
or jump over to details about `updating existing code to use the new APIs
<https://docs.pytest.org/en/latest/mark.htmlupdating-code>`_. (`3317
<https://github.com/pytest-dev/pytest/issues/3317>`_)

- Now when ``pytest.fixture`` is applied more than once to the same function a
``ValueError`` is raised. This buggy behavior would cause surprising problems
and if was working for a test suite it was mostly by accident. (`2334
<https://github.com/pytest-dev/pytest/issues/2334>`_)

- Support for Python 3.7's builtin ``breakpoint()`` method, see `Using the
builtin breakpoint function
<https://docs.pytest.org/en/latest/usage.htmlbreakpoint-builtin>`_ for
details. (`3180 <https://github.com/pytest-dev/pytest/issues/3180>`_)

- ``monkeypatch`` now supports a ``context()`` function which acts as a context
manager which undoes all patching done within the ``with`` block. (`3290
<https://github.com/pytest-dev/pytest/issues/3290>`_)

- The ``--pdb`` option now causes KeyboardInterrupt to enter the debugger,
instead of stopping the test session. On python 2.7, hitting CTRL+C again
exits the debugger. On python 3.2 and higher, use CTRL+D. (`3299
<https://github.com/pytest-dev/pytest/issues/3299>`_)

- pytest not longer changes the log level of the root logger when the
``log-level`` parameter has greater numeric value than that of the level of
the root logger, which makes it play better with custom logging configuration
in user code. (`3307 <https://github.com/pytest-dev/pytest/issues/3307>`_)


Bug Fixes
---------

- A rare race-condition which might result in corrupted ``.pyc`` files on
Windows has been hopefully solved. (`3008
<https://github.com/pytest-dev/pytest/issues/3008>`_)

- Also use iter_marker for discovering the marks applying for marker
expressions from the cli to avoid the bad data from the legacy mark storage.
(`3441 <https://github.com/pytest-dev/pytest/issues/3441>`_)

- When showing diffs of failed assertions where the contents contain only
whitespace, escape them using ``repr()`` first to make it easy to spot the
differences. (`3443 <https://github.com/pytest-dev/pytest/issues/3443>`_)


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

- Change documentation copyright year to a range which auto-updates itself each
time it is published. (`3303
<https://github.com/pytest-dev/pytest/issues/3303>`_)


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

- ``pytest`` now depends on the `python-atomicwrites
<https://github.com/untitaker/python-atomicwrites>`_ library. (`3008
<https://github.com/pytest-dev/pytest/issues/3008>`_)

- Update all pypi.python.org URLs to pypi.org. (`3431
<https://github.com/pytest-dev/pytest/issues/3431>`_)

- Detect `pytest_` prefixed hooks using the internal plugin manager since
``pluggy`` is deprecating the ``implprefix`` argument to ``PluginManager``.
(`3487 <https://github.com/pytest-dev/pytest/issues/3487>`_)

- Import ``Mapping`` and ``Sequence`` from ``_pytest.compat`` instead of
directly from ``collections`` in ``python_api.py::approx``. Add ``Mapping``
to ``_pytest.compat``, import it from ``collections`` on python 2, but from
``collections.abc`` on Python 3 to avoid a ``DeprecationWarning`` on Python
3.7 or newer. (`3497 <https://github.com/pytest-dev/pytest/issues/3497>`_)

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

[coveralls]

Coverage remained the same at 70.137% when pulling d988143 on pyup-update-pytest-3.5.1-to-3.6.0 into fc573e6 on master.