Update navsat proto to include covariance

[EmmanuelMess]

🦟 Bug fix

Fixes #488

Summary

This PR adds parity with https://github.com/ros2/common_interfaces/blob/master/sensor_msgs/msg/NavSatFix.msg message.
For completeness it also adds the velocity DOP.

Disclamer: I have no idea how this actually integrates with the rest of gazebo, and I couldn't find much info, so I would thank you if you tell me where I would need to add code to make it work with the gz ros2 bridge.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
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• All tests passed (See test coverage)
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[iche033]

I think updating msg fields breaks ABI compatibility of the generated msg library. Is that still the case @caguero?

If so, we would probably need to add a new navsat_with_covariance.proto message (similar to other *_with_covariance protos). In any case, we'll also then need to update gz-sensors' NavSatSensor to publish this msg with covariance to a new topic.

For ros_gz, a new convert function needs to be added in https://github.com/gazebosim/ros_gz/blob/ros2/ros_gz_bridge/include/ros_gz_bridge/convert/sensor_msgs.hpp for converting between the new gz navsat with covariance msg and ROS' NavSatFix msg.

[EmmanuelMess]

If so, we would probably need to add a new navsat_with_covariance.proto message (similar to other *_with_covariance protos). In any case, we'll also then need to update gz-sensors' NavSatSensor to publish this msg with covariance to a new topic.

Should the old message be deprecated in some way as part of this?

[iche033]

Should the old message be deprecated in some way as part of this?

I think we can keep the old message there. The new message will include the existing one, plus the other additional fields for covariances like the ones you added. Btw I see that the covariance fields have the Float_V type in other messages, e.g. pose_with_covariance.proto instead of Double_V. May be good to keep them consistent.