[Security] Bump sanitize from 5.1.0 to 5.2.1

Bumps [sanitize](https://github.com/rgrove/sanitize) from 5.1.0 to 5.2.1. **This update includes a security fix.**
- [Release notes](https://github.com/rgrove/sanitize/releases)
- [Changelog](https://github.com/rgrove/sanitize/blob/master/HISTORY.md)
- [Commits](https://github.com/rgrove/sanitize/compare/v5.1.0...v5.2.1)

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

Gemfile

@@ -26,7 +26,7 @@ gem "sqlite3", group: :sqlite
 gem "mysql2", "~> 0.5.3", group: :mysql
 
 gem "RedCloth"
-gem "sanitize", "~> 5.1"
+gem "sanitize", "~> 5.2"
 gem "will_paginate"
 gem "acts_as_list"
 gem "aasm", '~> 3.4.0'

Gemfile.lock

@@ -211,7 +211,7 @@ GEM
     ruby-progressbar (1.10.1)
     rubyzip (2.0.0)
     safe_yaml (1.0.5)
-    sanitize (5.1.0)
+    sanitize (5.2.1)
       crass (~> 1.0.2)
       nokogiri (>= 1.8.0)
       nokogumbo (~> 2.0)
@@ -318,7 +318,7 @@ DEPENDENCIES
   rails_autolink
   rspec-expectations
   rubocop (~> 0.83)
-  sanitize (~> 5.1)
+  sanitize (~> 5.2)
   sass-rails (~> 5.0)
   selenium-webdriver (~> 3.142)
   simplecov