Add single quotes to fix

Author: Olav de Haas

.travis.yml

@@ -28,7 +28,7 @@ env:
     - CCACHE_DIR=$HOME/.ccache # enables C/C++ caching in industrial_ci
     - BUILDER=colcon
     - CATKIN_LINT=pedantic
-    - CATKIN_LINT_ARGS=--ignore literal_project_name --ignore target_name_collision
+    - CATKIN_LINT_ARGS='--ignore literal_project_name --ignore target_name_collision'
     - UPSTREAM_WORKSPACE='.rosinstall -march/march_data_collector -march/march_gait_scheduler -march/march_gain_scheduling -march/march_gait_selection -march/march_launch -march/march_safety -march/march_sound_scheduler -march/march_state_machine'
     - AFTER_BUILD_TARGET_WORKSPACE='builder_run_build "$target_ws/install" "$target_ws" --cmake-target-skip-unavailable --cmake-target roslint'