Bump pygments from 2.4.2 to 2.7.4

Bumps [pygments](https://github.com/pygments/pygments) from 2.4.2 to 2.7.4.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.4.2...2.7.4)

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

requirements.txt

@@ -48,7 +48,7 @@ pycodestyle==2.5.0
     # via flake8
 pyflakes==2.1.1
     # via flake8
-pygments==2.4.2
+pygments==2.7.4
     # via -r requirements.in
 pyparsing==2.4.0
     # via packaging