Update pygments from 2.5.1 to 2.5.2

Author: pyup-bot

dev-requirements.txt

@@ -14,7 +14,7 @@ pip_check_reqs==2.0.3
 pydocstyle==4.0.1  # Lint docstrings
 pyenchant==2.0.0  # Bindings for a spellchecking sytem
 pygithub==1.44.1
-Pygments==2.5.1
+Pygments==2.5.2
 pylint==2.4.4  # Lint
 pyroma==2.6  # Packaging best practices checker
 pytest-cov==2.8.1  # Measure code coverage