docs(ffi): update changelog

Signed-of-by: Michael Goldenberg <m@mgoldenberg.net>

Author: mgoldenberg

bindings/matrix-sdk-ffi/CHANGELOG.md

@@ -8,14 +8,16 @@ All notable changes to this project will be documented in this file.
 
 Breaking changes:
 
-- `UploadParameters` includes a new field, `file_data: Option<Vec<u8>>`, which allows a foreign
-  language to read file contents natively and then pass those contents to the foreign function
-  when uploading a file through the `Timeline`.
+- `UploadParameters` replaces field `filename: String` with `source: UploadSource`.
+  `UploadSource` is an enum which may take a filename or a filename and bytes, which
+  allows a foreign language to read file contents natively and then pass those contents to
+  the foreign function when uploading a file through the `Timeline`.
   ([#4948](https://github.com/matrix-org/matrix-rust-sdk/pull/4948))
 
 Additions:
 
 - Add room topic string to `StateEventContent`
+- Add `UploadSource` for representing upload data - this is analogous to `matrix_sdk_ui::timeline::AttachmentSource`
 
 Breaking changes: