Update composer.json config section

Author: ivanvermeyen

composer.json

@@ -38,7 +38,11 @@
             ]
         }
     },
+    "config": {
+        "preferred-install": "dist",
+        "sort-packages": true,
+        "optimize-autoloader": true
+    },
     "minimum-stability": "stable",
-    "sort-packages": true,
-    "optimize-autoloader": true
+    "prefer-stable": true
 }