Pin sanitize to 5.2 (#32424).

git-svn-id: http://svn.redmine.org/redmine/trunk@21159 e93f8b46-1217-0410-a6f0-8f06a7374b81

Gemfile

@@ -51,7 +51,7 @@ end
 group :common_mark do
   gem "html-pipeline", "~> 2.13.2"
   gem "commonmarker", (RUBY_VERSION < '2.6' ? '0.21.0' : '~> 0.22')
-  gem "sanitize", "~> 5.1"
+  gem "sanitize", "~> 5.2"
 end
 
 # Include database gems for the adapters found in the database