Bump redcarpet from 3.3.3 to 3.5.0 in /docs/v3

Bumps [redcarpet](https://github.com/vmg/redcarpet) from 3.3.3 to 3.5.0.
- [Release notes](https://github.com/vmg/redcarpet/releases)
- [Changelog](https://github.com/vmg/redcarpet/blob/master/CHANGELOG.md)
- [Commits](vmg/redcarpet@v3.3.3...v3.5.0)

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

Author: dependabot[bot]

docs/v3/Gemfile.lock

@@ -107,7 +107,7 @@ GEM
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    redcarpet (3.3.3)
+    redcarpet (3.5.0)
     rouge (3.19.0)
     sassc (2.3.0)
       ffi (~> 1.9)