FIX assetic-bundle version

Author: sescandell

composer.json

@@ -22,7 +22,7 @@
     ],
     "require": {
         "symfony/symfony": ">=2.8,<4.0",
-        "symfony/assetic-bundle": "^2.3",
+        "symfony/assetic-bundle": "^2.7,>=2.7.1",
         "doctrine/common": "~2.2",
         "sensio/generator-bundle": "~3.0",
         "symfony2admingenerator/twig-generator": "~1.2,>=1.2.2",