[Security] Bump redcarpet from 2.1.1 to 3.2.3

Bumps [redcarpet](https://github.com/vmg/redcarpet) from 2.1.1 to 3.2.3. **This update includes a security fix.**
- [Release notes](https://github.com/vmg/redcarpet/releases)
- [Changelog](https://github.com/vmg/redcarpet/blob/master/CHANGELOG.md)
- [Commits](vmg/redcarpet@v2.1.1...v3.2.3)

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

Gemfile

@@ -28,7 +28,7 @@ gem 'jquery-rails'
 gem 'passenger'
 gem 'recaptcha', '3.0.0', :require => "recaptcha/rails"
 gem 'cocaine', '~>0.5.3'
-gem 'redcarpet', '2.1.1'
+gem 'redcarpet', '3.2.3'
 gem "skylight" # performance tracking via skylight.io
 
 gem 'rdiscount', '1.6.8'

Gemfile.lock

@@ -94,7 +94,7 @@ GEM
       json (~> 1.4)
     recaptcha (3.0.0)
       json
-    redcarpet (2.1.1)
+    redcarpet (3.2.3)
     rmagick (2.15.4)
     ruby-openid (2.7.0)
     skylight (1.7.2)
@@ -132,7 +132,7 @@ DEPENDENCIES
   rails (~> 3.2)
   rdiscount (= 1.6.8)
   recaptcha (= 3.0.0)
-  redcarpet (= 2.1.1)
+  redcarpet (= 3.2.3)
   rmagick
   ruby-openid
   skylight