feat: added offline collaboration example using appflowy_editor_sync_plugin (#1103)

* Adding offline collaboration example using appflowy_editor_sync_plugin

* Adapting example to a new  appflowy_editor_sync_plugin version.

* Revert "Adapting example to a new  appflowy_editor_sync_plugin version."

This reverts commit 7ea235f6f6ceb34d00a365fd05e82cdb6c5a8c67.

* increase flutter-version for testing workflow

* fix: auto_scrollable_widget adding lint ignore: invalide_use_of_protected_member.

lib/src/editor/editor_component/service/scroll/auto_scrollable_widget.dart

@@ -27,6 +27,7 @@ class _AutoScrollableWidgetState extends State<AutoScrollableWidget> {
 
   @override
   void dispose() {
+    // ignore: invalid_use_of_protected_member
     _scrollableState.dispose();
     super.dispose();
   }