Update composer.json

can we step the Contao version to < 4 :) ? Would like to try it in an 3.5.4 ...

Author: MoniqueHahnefeld

composer.json

@@ -18,7 +18,7 @@
     ],
     "require": {
         "php": ">=5.3",
-        "contao/core": ">=3.1,<3.4",
+        "contao/core": ">=3.1,<4.0.0",
         "contao-community-alliance/composer-plugin": "~2.0",
         "maximebf/debugbar": "~1.9"
     },