Bump redcarpet from 3.3.2 to 3.5.1

Bumps [redcarpet](https://github.com/vmg/redcarpet) from 3.3.2 to 3.5.1.
- [Release notes](https://github.com/vmg/redcarpet/releases)
- [Changelog](https://github.com/vmg/redcarpet/blob/master/CHANGELOG.md)
- [Commits](vmg/redcarpet@v3.3.2...v3.5.1)

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

Gemfile.lock

@@ -37,7 +37,7 @@ GEM
     mustache (1.0.2)
     rake (10.4.2)
     rdiscount (2.1.8)
-    redcarpet (3.3.2)
+    redcarpet (3.5.1)
     rocco (0.8.2)
       mustache
       redcarpet