Bump pygments.rb from 2.3.1 to 2.4.0

Bumps [pygments.rb](https://github.com/pygments/pygments.rb) from 2.3.1 to 2.4.0.
- [Release notes](https://github.com/pygments/pygments.rb/releases)
- [Changelog](https://github.com/pygments/pygments.rb/blob/master/CHANGELOG.adoc)
- [Commits](pygments/pygments.rb@v2.3.1...v2.4.0)

---
updated-dependencies:
- dependency-name: pygments.rb
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -105,7 +105,7 @@ GEM
     psych (4.0.6)
       stringio
     public_suffix (5.0.1)
-    pygments.rb (2.3.1)
+    pygments.rb (2.4.0)
     racc (1.6.2)
     rack (3.0.7)
     rackup (2.1.0)