Add support for Symfony version 4.x

Author: picodexter

CHANGELOG.md

@@ -6,7 +6,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
-*   (empty)
+*   Added support for Symfony version 4.x
 
 ### Changed
 

composer.json

@@ -15,7 +15,7 @@
         "php": "^5.6 || ^7.0",
         "defuse/php-encryption": "^2.0",
         "picodexter/parameter-encryption-bundle": "^1.0",
-        "symfony/framework-bundle": "^2.7 || ^3.0"
+        "symfony/framework-bundle": "^2.7 || ^3.0 || ^4.0"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^2.0",