add date of notification of acceptance

docs/participate.md

@@ -15,6 +15,8 @@ See [Call for Art](https://events.ccc.de/en/2023/11/22/37c3-call-for-art/) for d
 
 **Deadline: 03.12.2023**
 
+**Notification of acceptance: 03.12.2023**
+
 ## Call for Participation
 
 There will be multiple stages where talks can be held.
@@ -23,6 +25,8 @@ See [Call for Participation](https://www.ccc.de/en/updates/2023/37C3-CfP) for de
 
 **Deadline: 11.11.2023**
 
+**Notification of acceptance: 03.12.2023**
+
 ## Call for Assemblies
 
 Want to build and inhabit your own space with a group of friends? Register your assembly!