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

@@ -6,7 +6,7 @@ gem 'middleman-gh-pages', '~> 0.0.3'
 gem 'middleman-syntax', '~> 2.0.0'
 gem 'middleman-autoprefixer', '~> 2.4.4'
 gem 'rouge', '~> 1.9.0'
-gem 'redcarpet', '~> 3.3.2'
+gem 'redcarpet', '~> 3.5.1'
 
 gem 'rake', '~> 10.4.2'
 gem 'therubyracer', '~> 0.12.1', platforms: :ruby

Gemfile.lock

@@ -98,7 +98,7 @@ GEM
     rb-fsevent (0.10.2)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
-    redcarpet (3.3.4)
+    redcarpet (3.5.1)
     ref (2.0.0)
     rouge (1.9.1)
     sass (3.4.25)
@@ -138,7 +138,7 @@ DEPENDENCIES
   middleman-gh-pages (~> 0.0.3)
   middleman-syntax (~> 2.0.0)
   rake (~> 10.4.2)
-  redcarpet (~> 3.3.2)
+  redcarpet (~> 3.5.1)
   rouge (~> 1.9.0)
   therubyracer (~> 0.12.1)