Bump resource_retriever to 2.0.2. (ros2#461)

resource_retriever 2.0.2 was released to address an issue with the debian packages. 

https://github.com/ros2/rosdistro/blob/edf2e849c9efd0553dbd41f91b0ccd1a169c2328/ardent/distribution.yaml#L508-L520

ros/resource_retriever#19

Bump resource_retriever to 2.0.2. (ros2#461)

resource_retriever 2.0.2 was released to address an issue with the debian packages. 

https://github.com/ros2/rosdistro/blob/edf2e849c9efd0553dbd41f91b0ccd1a169c2328/ardent/distribution.yaml#L508-L520

ros/resource_retriever#19

typo on urdfdom hash