Bump pygments from 2.3.0 to 2.3.1

Bumps [pygments](http://pygments.org/) from 2.3.0 to 2.3.1.

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support

requirements.txt

@@ -6,7 +6,7 @@ sourced-engine==0.7.0
 parquet==1.2
 numpy==1.15.4
 humanize==0.5.1
-pygments==2.3.0
+pygments==2.3.1
 keras==2.2.4
 scikit-learn==0.20.0
 tqdm==4.28.1