Add a listener for the new component

dendrite-config.yaml

@@ -78,3 +78,4 @@ listen:
     federation_api: "localhost:7772"
     sync_api: "localhost:7773"
     media_api: "localhost:7774"
+    public_rooms_api: "localhost:7775"

src/github.com/matrix-org/dendrite/common/config/config.go

@@ -142,6 +142,7 @@ type Dendrite struct {
 		SyncAPI          Address `yaml:"sync_api"`
 		RoomServer       Address `yaml:"room_server"`
 		FederationSender Address `yaml:"federation_sender"`
+		PublicRoomsAPI   Address `yaml:"public_rooms_api"`
 	} `yaml:"listen"`
 }