Print what the deps script is doing.

docker/Dockerfile

@@ -29,7 +29,8 @@ RUN mkdir -p /home/j7s/workspace/
 COPY --chown=1000:1000 src/  /home/j7s/workspace/src
 WORKDIR /home/j7s/workspace
 RUN sudo apt update -y && \
-    rosdep install --ignore-src --simulate --reinstall --default-yes --from-path src > deps.bash && \
+    echo "set -ex" > deps.bash && \
+    rosdep install --ignore-src --simulate --reinstall --default-yes --from-path src >> deps.bash && \
     bash deps.bash && \
     sudo rm -rf /var/lib/apt/lists/*
 RUN . /opt/ros/$ROS_DISTRO/setup.sh && \