ChangeLog: Document behavior change for resource property

Change-Id: Id6e157aa191aaa4e24a9cd5c76abfe902fe43d44
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>

dist/changes-5.1.0

@@ -35,6 +35,9 @@ Third party components
  - A Window declared nested inside another Item or Window automatically
    becomes transient for (centered upon) its parent's window, if x and y
    were not explicitly specified
+ - The resources property of Item is now its own property independent
+   of QObject. It no longer returns all QObject children, or explicitly
+   sets QObject parent. The resources property now behaves as documented.
 
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