Updating toc file adding email events

Author: anmolbohra97

articles/event-grid/toc.yml

@@ -137,6 +137,8 @@ items:
             href: communication-services-voice-video-events.md
           - name: Presence Events
             href: communication-services-presence-events.md
+          - name: Email events
+            href: communication-services-email-events.md
         - name: Azure Container Registry
           href: event-schema-container-registry.md
         - name: Azure Event Hubs