Add "Advancing the spec to stage 2" to October WG (#262)

Author: benjie

working-group/agendas/2023/2023-10-26.md

@@ -115,3 +115,4 @@ Denis Badurina          | @enisdenjo             | The Guild               | Sar
 1. Review previous meeting's action items (5m, Organizer)
 1. Review persisted operations RFC (10m, @JoviDeCroock)
 1. ["Accept" header PR](https://github.com/graphql/graphql-over-http/pull/227) decision (15m, Benjie)
+1. Advancing the spec to stage 2 (remaining time, Benjie)