Fix agent launch (#78) (#80)

Co-authored-by: Your Name <you@example.com>
(cherry picked from commit 69f17c28a8)

Co-authored-by: Pablo Garrido <pablogs9@gmail.com>

micro_ros_agent/launch/micro_ros_agent_launch.py

@@ -7,6 +7,6 @@ def generate_launch_description():
             package='micro_ros_agent',
             executable='micro_ros_agent',
             name='micro_ros_agent',
-            arguments={'udp4 --port 8888 -v6'}
+            arguments={"udp4", "-p", "8888", "-v6"}
         )
     ])