Add additional udpsink to gscam GStreamer launch string

Author: hmakelin

docker/gscam/gscam_params.yaml

@@ -2,6 +2,11 @@ gscam_publisher:
   ros__parameters:
     gscam_config: >
       udpsrc port=5600 caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264"
+      ! tee name=t
+      ! queue
+      ! udpsink host=0.0.0.0 port=5601
+      t.
+      ! queue
       ! rtph264depay
       ! avdec_h264
       ! videoconvert