Change cp command to use -rfL option (#335)

Resolve symlinks from the `extra_packages` directory

(cherry picked from commit 2f73852)

Author: Caedael

libmicroros.mk

@@ -83,7 +83,7 @@ $(EXTENSIONS_DIR)/micro_ros_src/src:
 	touch src/rcl/rcl_yaml_param_parser/COLCON_IGNORE; \
 	touch src/ros2_tracing/test_tracetools/COLCON_IGNORE; \
 	touch src/ros2_tracing/lttngpy/COLCON_IGNORE; \
-	cp -rf $(EXTRA_ROS_PACKAGES) src/extra_packages || :; \
+	cp -rfL $(EXTRA_ROS_PACKAGES) src/extra_packages || :; \
 	test -f src/extra_packages/extra_packages.repos && cd src/extra_packages && vcs import --input extra_packages.repos || :;