Bump redcarpet from 3.3.4 to 3.5.1

Bumps [redcarpet](https://github.com/vmg/redcarpet) from 3.3.4 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@v3.3.4...v3.5.1)

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

Author: dependabot[bot]

Gemfile.lock

@@ -50,7 +50,7 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)
       ffi (~> 1.0)
-    redcarpet (3.3.4)
+    redcarpet (3.5.1)
     ref (2.0.0)
     rouge (2.2.1)
     safe_yaml (1.0.5)