Skip existing repos in vcs (#419)

(cherry picked from commit ecdd1ab)

Author: pablogs9

scripts/create_ws.sh

@@ -42,8 +42,8 @@ fi
 # ROS_DISTRO SPECIFIC
 curl -s https://raw.githubusercontent.com/ros2/ros2/master/ros2.repos |\
     ros2 run micro_ros_setup yaml_filter.py ${PACKAGES} > ros2.repos
-vcs import --input ros2.repos
-vcs import --input $REPOS
+vcs import --input ros2.repos --skip-existing
+vcs import --input $REPOS --skip-existing
 
 popd >/dev/null