Meta: Update slides link in the README

Author: gibson042

README.md

@@ -2,7 +2,7 @@
 
 A proposal for extending `JSON.parse` behavior to grant reviver functions access to the input source text and extending `JSON.stringify` behavior to support object placeholders for raw JSON text primitives.
 
-[2022 June slides](https://docs.google.com/presentation/d/1C2RLbE-SS8ldlQPfXgsvKJBrEIZb4s57pOn-LxBNaC0/)
+[2023 September slides](https://docs.google.com/presentation/d/1pg1gnNeMIcAbwq-CdQE7vlSldlNZ5q2hC5OA-U8ScI8/edit?usp=sharing)
 
 [original 2018 September slides](https://docs.google.com/presentation/d/1PB0HCOxWZikFmTAqR5U2ZZjEiDV7NjhPN_-SK5NNG0w/edit?usp=sharing)