fix: reload posts when the parent widget has rebuilt on the timeline screen

This way if the service passed to us is changed we'll update our posts from it instead
of keeping the ones from the previous service.

packages/flutter_timeline_view/lib/src/screens/timeline_screen.dart

@@ -109,6 +109,15 @@ class _TimelineScreenState extends State<TimelineScreen> {
     });
   }
 
+  @override
+  void didUpdateWidget(covariant TimelineScreen oldWidget) {
+    super.didUpdateWidget(oldWidget);
+
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      unawaited(loadPosts());
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     if (isLoading && widget.posts == null) {