move ament-lint to pre-commit completely

We had the ament-lint things in there twice which would have to be maintained twice.
Since we are running pre-commit in the CI anyway, we can easily drop the extra
ci step.

Author: Felix Exner

.github/workflows/ci-ros-lint.yml

@@ -116,6 +116,7 @@ repos:
         stages: [commit]
         entry: ament_copyright
         language: system
+        args: ['--exclude', 'ur_robot_driver/doc/conf.py']
 
   # Docs - RestructuredText hooks
   - repo: https://github.com/PyCQA/doc8