Preparing changelog

Modules/Media/changelog.yml

 url: https://github.com/AsgardCms/Platform
 versions:
+    "3.0.0@unreleased":
+        added:
+            - New <code>MaxFolderSizeRule</code> class, using new validator classes in laravel 5.5
+        changed:
+            - Using return type hints in <code>MediaController</code>
     "2.5.0":
         added:
             - <code>FileWasCreated</code> event