Update pytest to 4.2.0 (#535)

This PR updates [pytest](https://pypi.org/project/pytest) from **4.1.1** to **4.2.0**.



<details>
  <summary>Changelog</summary>
  
  
   ### 4.2.0
   ```
   =========================

Features
--------

- `3094 &lt;https://github.com/pytest-dev/pytest/issues/3094&gt;`_: `Class xunit-style &lt;https://docs.pytest.org/en/latest/xunit_setup.html&gt;`__ functions and methods
  now obey the scope of *autouse* fixtures.

  This fixes a number of surprising issues like ``setup_method`` being called before session-scoped
  autouse fixtures (see `517 &lt;https://github.com/pytest-dev/pytest/issues/517&gt;`__ for an example).


- `4627 &lt;https://github.com/pytest-dev/pytest/issues/4627&gt;`_: Display a message at the end of the test session when running under Python 2.7 and 3.4 that pytest 5.0 will no longer
  support those Python versions.


- `4660 &lt;https://github.com/pytest-dev/pytest/issues/4660&gt;`_: The number of *selected* tests now are also displayed when the ``-k`` or ``-m`` flags are used.


- `4688 &lt;https://github.com/pytest-dev/pytest/issues/4688&gt;`_: ``pytest_report_teststatus`` hook now can also receive a ``config`` parameter.


- `4691 &lt;https://github.com/pytest-dev/pytest/issues/4691&gt;`_: ``pytest_terminal_summary`` hook now can also receive a ``config`` parameter.



Bug Fixes
---------

- `3547 &lt;https://github.com/pytest-dev/pytest/issues/3547&gt;`_: ``--junitxml`` can emit XML compatible with Jenkins xUnit.
  ``junit_family`` INI option accepts ``legacy|xunit1``, which produces old style output, and ``xunit2`` that conforms more strictly to https://github.com/jenkinsci/xunit-plugin/blob/xunit-2.3.2/src/main/resources/org/jenkinsci/plugins/xunit/types/model/xsd/junit-10.xsd


- `4280 &lt;https://github.com/pytest-dev/pytest/issues/4280&gt;`_: Improve quitting from pdb, especially with ``--trace``.

  Using ``q[quit]`` after ``pdb.set_trace()`` will quit pytest also.


- `4402 &lt;https://github.com/pytest-dev/pytest/issues/4402&gt;`_: Warning summary now groups warnings by message instead of by test id.

  This makes the output more compact and better conveys the general idea of how much code is
  actually generating warnings, instead of how many tests call that code.


- `4536 &lt;https://github.com/pytest-dev/pytest/issues/4536&gt;`_: ``monkeypatch.delattr`` handles class descriptors like ``staticmethod``/``classmethod``.


- `4649 &lt;https://github.com/pytest-dev/pytest/issues/4649&gt;`_: Restore marks being considered keywords for keyword expressions.


- `4653 &lt;https://github.com/pytest-dev/pytest/issues/4653&gt;`_: ``tmp_path`` fixture and other related ones provides resolved path (a.k.a real path)


- `4667 &lt;https://github.com/pytest-dev/pytest/issues/4667&gt;`_: ``pytest_terminal_summary`` uses result from ``pytest_report_teststatus`` hook, rather than hardcoded strings.


- `4669 &lt;https://github.com/pytest-dev/pytest/issues/4669&gt;`_: Correctly handle ``unittest.SkipTest`` exception containing non-ascii characters on Python 2.


- `4680 &lt;https://github.com/pytest-dev/pytest/issues/4680&gt;`_: Ensure the ``tmpdir`` and the ``tmp_path`` fixtures are the same folder.


- `4681 &lt;https://github.com/pytest-dev/pytest/issues/4681&gt;`_: Ensure ``tmp_path`` is always a real path.



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

- `4643 &lt;https://github.com/pytest-dev/pytest/issues/4643&gt;`_: Use ``a.item()`` instead of the deprecated ``np.asscalar(a)`` in ``pytest.approx``.

  ``np.asscalar`` has been `deprecated &lt;https://github.com/numpy/numpy/blob/master/doc/release/1.16.0-notes.rstnew-deprecations&gt;`__ in ``numpy 1.16.``.


- `4657 &lt;https://github.com/pytest-dev/pytest/issues/4657&gt;`_: Copy saferepr from pylib
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/pytest
  - Changelog: https://pyup.io/changelogs/pytest/
  - Homepage: https://docs.pytest.org/en/latest/
</details>

requirements.txt

@@ -415,9 +415,9 @@ zopfli==0.1.6 \
     --hash=sha256:ed2293c11c2685bbd70bad0103285279406a77622e06de794d59c2180fecaa6a
 huey==1.10.5 \
     --hash=sha256:c0ead41821462e111873102075addaa4d7040fbda52db8834c4302207758d5e2
-pytest==4.1.1 \
-    --hash=sha256:41568ea7ecb4a68d7f63837cf65b92ce8d0105e43196ff2b26622995bb3dc4b2 \
-    --hash=sha256:c3c573a29d7c9547fb90217ece8a8843aa0c1328a797e200290dc3d0b4b823be
+pytest==4.2.0 \
+    --hash=sha256:6ac6d467d9f053e95aaacd79f831dbecfe730f419c6c7022cb316b365cd9199d \
+    --hash=sha256:65aeaa77ae87c7fc95de56285282546cfa9c886dc8e5dc78313db1c25e21bc07
 pytest-django==3.4.5 \
     --hash=sha256:e88e471d3d0f9acfb6293bb03d0ee8a33ed978734e92ea6b5312163a6c9e87cc \
     --hash=sha256:1a5d33be930e3172fa238643a380414dc369fe8fa4b3c3de25e59ed142950736