Merge branch '5.2' into 5.x

* 5.2:
  [Finder] Fix gitignore regex build with "**"
  Fixed deprecation warnings about passing null as parameter
  [Security] Keep Bulgarian wording consistent across all texts.
  Migrate configuration file for PHP CS Fixer 2.19/3.0
  [Form] Replace broken ServerParams mock
  [Mailer] Fix SES API call with UTF-8 Addresses

Author: fabpot

Constraints/IpValidator.php

@@ -93,7 +93,7 @@ public function validate($value, Constraint $constraint)
                break;
 
             default:
-                $flag = null;
+                $flag = 0;
                 break;
         }