Bump pygments from 2.2.0 to 2.7.4

Bumps [pygments](https://github.com/pygments/pygments) from 2.2.0 to 2.7.4.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](https://github.com/pygments/pygments/compare/2.2.0...2.7.4)

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

requirements.txt

@@ -11,7 +11,7 @@ MarkupSafe==0.23
 pudb==2017.1.1
 py==1.4.32
 pycrypto
-Pygments==2.2.0
+Pygments==2.7.4
 pytest==3.0.6
 pytz==2016.10
 requests