Bump pygments from 2.3.1 to 2.4.1

Bumps [pygments](https://bitbucket.org/birkenfeld/pygments-main) from 2.3.1 to 2.4.1.
- [Changelog](https://bitbucket.org/birkenfeld/pygments-main/src/default/CHANGES)
- [Commits](https://bitbucket.org/birkenfeld/pygments-main/commits)

Author: dependabot-preview[bot]

requirements.txt

@@ -24,7 +24,7 @@ pluggy==0.11.0
 py==1.7.0
 pycparser==2.19
 pyflakes==2.1.1
-Pygments==2.3.1
+Pygments==2.4.1
 pyparsing==2.3.0
 pytest==4.5.0
 pytest-cache==1.0