suggest ext-gd or ext-imagick

Author: youchenlee

composer.json

@@ -26,6 +26,10 @@
     "illuminate/support": ">=4.2.0",
     "intervention/image": "2.*"
   },
+  "suggest": {
+    "ext-gd": "to use GD library based image processing.",
+    "ext-imagick": "to use Imagick based image processing."
+  },
   "autoload": {
     "psr-4": {
       "Unisharp\\Laravelfilemanager\\": "src/"