Update composer.json

Author: ngodfraind

composer.json

@@ -14,7 +14,7 @@
     ],
     "require": {
         "php": ">=5.4.1",
-        "claroline/core-bundle": "~5.0"
+        "claroline/core-bundle": "~6.0"
     },
     "autoload": {
         "psr-0": { "Claroline\\ActivityToolBundle": "" }