removed automatically injected config

Author: transistive

composer.json

@@ -57,10 +57,5 @@
     "infect": "XDEBUG_MODE=coverage infection --show-mutations"
   },
   "minimum-stability": "stable",
-  "prefer-stable": true,
-  "config": {
-    "allow-plugins": {
-      "infection/extension-installer": false
-    }
-  }
+  "prefer-stable": true
 }