ogma-cli: Update README to demonstrate robotics. Refs nasa#172.

The README shows an image of a monitor in X-Plane, but nothing related
to robotics, even though it is one of the main use cases for Copilot.
This should be demonstrated more clearly.

This commit updates the README to show a video of Ogma-generated
monitors running on a ROS system, integrated into Gazebo.

ogma-cli/README.md

@@ -27,6 +27,12 @@ verification framework that generates hard real-time C99 code.
   <i>Integration of monitors into larger applications (e.g., simulators).</i>
 </p>
 
+<p align="center">
+  <img src="https://raw.githubusercontent.com/nasa/ogma/gh-pages/images/ros.gif" alt="Monitoring within ROS simulation video">
+  <br />
+  <i>Integration of monitors into robotics applications.</i>
+</p>
+
 ## Table of Contents
 
 - [Installation](#installation)