Merge #31

31: Update pytest-cov to 2.6.0 r=rehandalal a=pyup-bot


This PR updates [pytest-cov](https://pypi.org/project/pytest-cov) from **2.5.1** to **2.6.0**.



<details>
  <summary>Changelog</summary>
  
  
   ### 2.6.0
   ```
   ------------------

* Dropped support for Python &lt; 3.4, Pytest &lt; 3.5 and Coverage &lt; 4.4.
* Fixed some documentation formatting. Contributed by Jean Jordaan and Julian.
* Added an example with ``addopts`` in documentation. Contributed by Samuel Giffard in
  `195 &lt;https://github.com/pytest-dev/pytest-cov/pull/195&gt;`_.
* Fixed ``TypeError: &#39;NoneType&#39; object is not iterable`` in certain xdist configurations. Contributed by Jeremy Bowman in
  `213 &lt;https://github.com/pytest-dev/pytest-cov/pull/213&gt;`_.
* Added a ``no_cover`` marker and fixture. Fixes
  `78 &lt;https://github.com/pytest-dev/pytest-cov/issues/78&gt;`_.
* Fixed broken ``no_cover`` check when running doctests. Contributed by Terence Honles in
  `200 &lt;https://github.com/pytest-dev/pytest-cov/pull/200&gt;`_.
* Fixed various issues with path normalization in reports (when combining coverage data from parallel mode). Fixes
  `130 &lt;https://github.com/pytest-dev/pytest-cov/issues/161&gt;`_.
  Contributed by Ryan Hiebert &amp; Ionel Cristian Mărieș in
  `178 &lt;https://github.com/pytest-dev/pytest-cov/pull/178&gt;`_.
* Report generation failures don&#39;t raise exceptions anymore. A warning will be logged instead. Fixes
  `161 &lt;https://github.com/pytest-dev/pytest-cov/issues/161&gt;`_.
* Fixed multiprocessing issue on Windows (empty env vars are not passed). Fixes
  `165 &lt;https://github.com/pytest-dev/pytest-cov/issues/165&gt;`_.
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/pytest-cov
  - Changelog: https://pyup.io/changelogs/pytest-cov/
  - Repo: https://github.com/pytest-dev/pytest-cov
</details>



Co-authored-by: pyup-bot <github-bot@pyup.io>

requirements-dev.txt

@@ -1,4 +1,4 @@
 -r requirements.txt
 flake8==3.5.0
 pytest==3.7.4
-pytest-cov==2.5.1
+pytest-cov==2.6.0