Updated the version of the security checker

Author: javiereguiluz

composer.json

@@ -13,7 +13,7 @@
         "erusev/parsedown": "^1.6",
         "ezyang/htmlpurifier": "^4.9",
         "sensio/framework-extra-bundle": "^5.0",
-        "sensiolabs/security-checker": "dev-master",
+        "sensiolabs/security-checker": "^5.0",
         "symfony/asset": "4.2.0-beta1",
         "symfony/expression-language": "4.2.0-beta1",
         "symfony/flex": "^1.1",