A few small fixes for installing RHEL binary. (#4451)

Signed-off-by: Chris Lalancette <[email protected]>

Author: clalancette

source/Installation/Alternatives/RHEL-Install-Binary.rst

@@ -109,7 +109,9 @@ Install dependencies using rosdep
 
 .. code-block:: bash
 
-   rosdep install --from-paths ~/ros2_{DISTRO}/ros2-linux/share --ignore-src -y --skip-keys "cyclonedds fastcdr fastrtps rti-connext-dds-6.0.1 urdfdom_headers"
+   sudo rosdep init
+   rosdep update
+   rosdep install --from-paths ~/ros2_{DISTRO}/ros2-linux/share --ignore-src -y --skip-keys "cyclonedds fastcdr fastrtps iceoryx_binding_c rti-connext-dds-6.0.1 urdfdom_headers"
 
 Install additional RMW implementations (optional)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^