Update pytest to 3.8.2 (#1195)

This PR updates [pytest](https://pypi.org/project/pytest) from **3.8.1** to **3.8.2**.



<details>
  <summary>Changelog</summary>
  
  
   ### 3.8.2
   ```
   =========================

Deprecations and Removals
-------------------------

- `4036 &lt;https://github.com/pytest-dev/pytest/issues/4036&gt;`_: The ``item`` parameter of ``pytest_warning_captured`` hook is now documented as deprecated. We realized only after
  the ``3.8`` release that this parameter is incompatible with ``pytest-xdist``.

  Our policy is to not deprecate features during bugfix releases, but in this case we believe it makes sense as we are
  only documenting it as deprecated, without issuing warnings which might potentially break test suites. This will get
  the word out that hook implementers should not use this parameter at all.

  In a future release ``item`` will always be ``None`` and will emit a proper warning when a hook implementation
  makes use of it.



Bug Fixes
---------

- `3539 &lt;https://github.com/pytest-dev/pytest/issues/3539&gt;`_: Fix reload on assertion rewritten modules.


- `4034 &lt;https://github.com/pytest-dev/pytest/issues/4034&gt;`_: The ``.user_properties`` attribute of ``TestReport`` objects is a list
  of (name, value) tuples, but could sometimes be instantiated as a tuple
  of tuples.  It is now always a list.


- `4039 &lt;https://github.com/pytest-dev/pytest/issues/4039&gt;`_: No longer issue warnings about using ``pytest_plugins`` in non-top-level directories when using ``--pyargs``: the
  current ``--pyargs`` mechanism is not reliable and might give false negatives.


- `4040 &lt;https://github.com/pytest-dev/pytest/issues/4040&gt;`_: Exclude empty reports for passed tests when ``-rP`` option is used.


- `4051 &lt;https://github.com/pytest-dev/pytest/issues/4051&gt;`_: Improve error message when an invalid Python expression is passed to the ``-m`` option.


- `4056 &lt;https://github.com/pytest-dev/pytest/issues/4056&gt;`_: ``MonkeyPatch.setenv`` and ``MonkeyPatch.delenv`` issue a warning if the environment variable name is not ``str`` on Python 2.

  In Python 2, adding ``unicode`` keys to ``os.environ`` causes problems with ``subprocess`` (and possible other modules),
  making this a subtle bug specially susceptible when used with ``from __future__ import unicode_literals``.



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

- `3928 &lt;https://github.com/pytest-dev/pytest/issues/3928&gt;`_: Add possible values for fixture scope to docs.
   ```
   
  
</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

@@ -206,9 +206,9 @@ flake8==3.5.0 \
 mock==2.0.0 \
     --hash=sha256:5ce3c71c5545b472da17b72268978914d0252980348636840bd34a00b5cc96c1 \
     --hash=sha256:b158b6df76edd239b8208d481dc46b6afd45a846b7812ff0ce58971cf5bc8bba
-pytest==3.8.1 \
-    --hash=sha256:0a72d8a9f559c006ba153e0c9b4838efd7b656cf1f993747ba7128770d6eb12c \
-    --hash=sha256:95529588ff4e85114a0b0ad8e9cf0131ca47d46b28230e25366c5aba66b1d854
+pytest==3.8.2 \
+    --hash=sha256:7e258ee50338f4e46957f9e09a0f10fb1c2d05493fa901d113a8dafd0790de4e \
+    --hash=sha256:9332147e9af2dcf46cd7ceb14d5acadb6564744ddff1fe8c17f0ce60ece7d9a2
 coverage==4.5.1 \
     --hash=sha256:7608a3dd5d73cb06c531b8925e0ef8d3de31fed2544a7de6c63960a1e73ea4bc \
     --hash=sha256:3a2184c6d797a125dca8367878d3b9a178b6fdd05fdc2d35d758c3006a1cd694 \