I put together a quick python script to automate the task of migrating a package from catkin to ament. The script just follows the instructions in the ROS 2 migration guide (note that the script is not yet complete).
You can find the script at: ros2-support/scripts/catkin-to-ament.py at master · bponsler/ros2-support · GitHub
Additionally a brief explanation of how to use the script here: ros2-support/tutorials/port-catkin-to-ament.md at master · bponsler/ros2-support · GitHub
As the tutorial says, the script hasn’t been extensively tested and is unlikely to work perfectly but may help reduce the burden of migrating.
Enjoy.