[CI] Force docker-compose to pull newer versions of images

docker_test.sh

@@ -56,6 +56,8 @@ for v in $(docker-compose config --volumes); do
 done
 
 echo -e "\n==== Pull new versions of images ===="
+# For some reasons, sometime docker-compose does not pull the newer image. Force this!
+docker-compose config | grep "image:" | cut -d ':' -f 2- | xargs docker image rm || true
 docker-compose pull
 
 echo -e "\n==== Replace production URL with testing URL in all files ===="