Update pytest to 3.9.2 (#395)

This PR updates [pytest](https://pypi.org/project/pytest) from **3.9.1** to **3.9.2**.



<details>
  <summary>Changelog</summary>
  
  
   ### 3.9.2
   ```
   =========================

Bug Fixes
---------

- `2909 &lt;https://github.com/pytest-dev/pytest/issues/2909&gt;`_: Improve error message when a recursive dependency between fixtures is detected.


- `3340 &lt;https://github.com/pytest-dev/pytest/issues/3340&gt;`_: Fix logging messages not shown in hooks ``pytest_sessionstart()`` and ``pytest_sessionfinish()``.


- `3533 &lt;https://github.com/pytest-dev/pytest/issues/3533&gt;`_: Fix unescaped XML raw objects in JUnit report for skipped tests


- `3691 &lt;https://github.com/pytest-dev/pytest/issues/3691&gt;`_: Python 2: safely format warning message about passing unicode strings to ``warnings.warn``, which may cause
  surprising ``MemoryError`` exception when monkey patching ``warnings.warn`` itself.


- `4026 &lt;https://github.com/pytest-dev/pytest/issues/4026&gt;`_: Improve error message when it is not possible to determine a function&#39;s signature.


- `4177 &lt;https://github.com/pytest-dev/pytest/issues/4177&gt;`_: Pin ``setuptools&gt;=40.0`` to support ``py_modules`` in ``setup.cfg``


- `4179 &lt;https://github.com/pytest-dev/pytest/issues/4179&gt;`_: Restore the tmpdir behaviour of symlinking the current test run.


- `4192 &lt;https://github.com/pytest-dev/pytest/issues/4192&gt;`_: Fix filename reported by ``warnings.warn`` when using ``recwarn`` under python2.
   ```
   
  
</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

@@ -404,9 +404,9 @@ zopfli==0.1.4 \
     --hash=sha256:df7f84a01c0d8c8936e764e63fd0478aa526dc405ee2ad437e633b28cf824141 \
     --hash=sha256:ea204478f5dd4b7c03ec8a25ac5512f5cd85b15e001724289d1676a52c4c1633 \
     --hash=sha256:f5d7840833608f1be3a5f928dbcc0a5ff45ebd8040ea6177864f61a72b773423
-pytest==3.9.1 \
-    --hash=sha256:10e59f84267370ab20cec9305bafe7505ba4d6b93ecbf66a1cce86193ed511d5 \
-    --hash=sha256:8c827e7d4816dfe13e9329c8226aef8e6e75d65b939bc74fda894143b6d1df59
+pytest==3.9.2 \
+    --hash=sha256:6f6c1efc8d0ccc21f8f6c34d8330baca883cf109b66b3df954b0a117e5528fb4 \
+    --hash=sha256:212be78a6fa5352c392738a49b18f74ae9aeec1040f47c81cadbfd8d1233c310
 pytest-django==3.4.3 \
     --hash=sha256:49e9ffc856bc6a1bec1c26c5c7b7213dff7cc8bc6b64d624c4d143d04aff0bcf \
     --hash=sha256:b379282feaf89069cb790775ab6bbbd2bd2038a68c7ef9b84a41898e0b551081