Bump pygments from 2.2.0 to 2.7.4 (#108)

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](pygments/pygments@2.2.0...2.7.4)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 Trac==1.2.6
-Pygments==2.2.0
+Pygments==2.7.4
 dnspython==1.15
 spambayes == 1.1b1
 psycopg2-binary==2.7.6.1