Implement note visuals update method.

rhythm_game/note/visual/tap/tap_note.gd

@@ -1,14 +1,16 @@
 class_name TapNote extends NoteVisual
 
+var hit_beat: float = -999.0
+
 var id: int = -1
 
-#TODO: Add all the members needed so a note can be updated.
-
 func reset() -> void:
 	id = -1
+	hit_beat = -999.0
+	position = Vector2(0, 9999.0)
 
 func in_use() -> bool:
 	return id >= 0
 
 func update(beat: float) -> void:
-	pass
+	position.y = _calculate_scroll(hit_beat, beat)