Bump pygments from 2.6.1 to 2.7.4

Bumps [pygments](https://github.com/pygments/pygments) from 2.6.1 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/2.6.1...2.7.4)

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

README.md

@@ -122,7 +122,7 @@ virtualenv venv
 
 ```
 source venv/bin/activate
-pip install -r requirements.txt
+pip intall -r requirements.txt
 ```
 
 * Make the script executable