[vm/ffi] Add Changelog for Array.elements change

Follow-up to https://dart-review.googlesource.com/c/sdk/+/414821

Bug: #45508
Change-Id: I46380486fb3758e2a99c829a33e3b75c96bfab52
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/423720
Reviewed-by: Daco Harkes <[email protected]>
Commit-Queue: Michael Goderbauer <[email protected]>

Author: goderbauer

CHANGELOG.md

@@ -27,6 +27,10 @@
   breaking change in 3.0.0 that removed the `registerElement` APIs. See
   [#53264](https://github.com/dart-lang/sdk/issues/53264) for details.
 
+#### `dart:ffi`
+
+- Added `Array.elements` which exposes an `Iterable` over the `Array`'s content.
+
 ### Tools
 
 #### Analyzer