properly scoping the dependency

Author: dmolsen

composer.json

@@ -25,7 +25,7 @@
   },
   "require": {
     "php":              ">=5.4",
-    "pattern-lab/core": "^2.0.0",
+    "pattern-lab/core": "^2.3.0",
     "fzaninotto/faker": "^1.0.0"
   },
   "extra": {