Updating gaufrette dependency.

Use latest stable.

Author: jenkoian

composer.json

@@ -5,7 +5,7 @@
     "require": {
         "php": ">=5.4.0",
         "league/flysystem": "^1.0",
-        "knplabs/gaufrette": "~0.4"
+        "knplabs/gaufrette": "^0.2"
     },
     "require-dev": {
         "phpunit/phpunit": "~4.8"
@@ -30,6 +30,5 @@
             "dev-master": "1.0-dev"
         }
     },
-    "minimum-stability": "dev",
-    "prefer-stable": true
+    "minimum-stability": "stable"
 }