Test restore linux/arm64 on agent docker

Signed-off-by: Antón Casas <antoncasas@eprosima.com>

Author: 4ntn

.github/workflows/generate_agent_docker.yml

@@ -37,5 +37,5 @@ jobs:
         with:
           context: ./micro-ROS-Agent/
           push: true
-          platforms: linux/amd64
+          platforms: linux/amd64,linux/arm64
           tags: microros/micro-ros-agent:${{ matrix.ros_distribution }}