add debian:sid test

Author: k-okada

.github/workflows/config.yml

@@ -17,6 +17,7 @@ jobs:
           - DOCKER_IMAGE: ubuntu:bionic
           - DOCKER_IMAGE: ubuntu:focal
           - DOCKER_IMAGE: debian:stretch
+          - DOCKER_IMAGE: debian:sid
           - DOCKER_IMAGE: ubuntu:trusty
             ROS_DISTRO: indigo
           - DOCKER_IMAGE: ubuntu:xenial