event brokers documentation should say 'url' instead of 'host' (RasaHQ#5811)

* event brokers documentation should say 'url' instead of 'host'

* Create 5811.docs.rst

Co-authored-by: Roberto <[email protected]>

Author: cristianmtr

changelog/5811.docs.rst

@@ -0,0 +1 @@
+event brokers documentation should say 'url' instead of 'host'

docs/api/event-brokers.rst

@@ -273,7 +273,7 @@ PostgreSQL databases can be used as well:
 
     event_broker:
       type: SQL
-      host: 127.0.0.1
+      url: 127.0.0.1
       port: 5432
       dialect: postgresql
       username: myuser