Merge pull request #4 from level-level/release-1.0.0

Update composer.json

Author: Willemijnr

composer.json

@@ -8,6 +8,6 @@
         }
     ],
     "require": {
-        "level-level/clarkson-core": "1.0.0-rc3"
+        "level-level/clarkson-core": "^1.0.0"
     }
 }