Update packages/flutter/CHANGELOG.md

Author: mtrezza

packages/flutter/CHANGELOG.md

@@ -1,9 +1,12 @@
-## [4.0.0](https://github.com/parse-community/Parse-SDK-Flutter/compare/flutter-3.1.3...flutter-4.0.0) (2023-03-09)
+## Unreleased (master branch)
 
-### Breaking change
+### BREAKING CHANGES
+
+* The source file name of the Flutter package has changed; to import the Flutter package use `parse_server_sdk_flutter.dart` instead of `parse_server_sdk.dart` ([#846](https://github.com/parse-community/Parse-SDK-Flutter/pull/846))
+
+### Features
 
-* Change the source file name ([#845](https://github.com/parse-community/Parse-SDK-Flutter/issues/845))
-  Rather than importing `parse_server_sdk.dart` now you need to import `parse_server_sdk_flutter.dart`
+* Rename Flutter package source file to `parse_server_sdk_flutter.dart` ([#846](https://github.com/parse-community/Parse-SDK-Flutter/pull/846))
 
 ## [3.1.4](https://github.com/parse-community/Parse-SDK-Flutter/compare/flutter-3.1.3...flutter-3.1.4) (2023-03-01)