docker: allow rosdep install to continue on error

Signed-off-by: Rhys Mainwaring <rhys.mainwaring@me.com>

docker/Dockerfile

@@ -40,5 +40,5 @@ RUN wstool update -t src -j4
 RUN apt-get update \
     && rosdep update \
     && source /opt/ros/noetic/setup.bash \
-    && rosdep install --from-paths src --ignore-src -y \
+    && rosdep install --from-paths src --ignore-src -r -y \
     && rm -rf /var/lib/apt/lists/*