updated dependencies

Author: n.plaschke

composer.json

@@ -14,7 +14,7 @@
   "name": "openskill/datatable",
   "require": {
     "php": ">=5.4.0",
-    "symfony/http-foundation": ">=2.7.*",
+    "symfony/http-foundation": "2.7.*",
     "illuminate/support": ">=4.2.0",
     "illuminate/contracts": ">=4.2.0"
   },