Added prune (for docker-desktop)

git-svn-id: https://redmine.imt-atlantique.fr/svn/xaal/code/Python/branches/0.7@3180 b32b6428-25c9-4566-ad07-03861ab6144f

docker/xaal-debian/test.sh

@@ -6,3 +6,4 @@ NAME=xaal-debian
 docker buildx build -t ${NAME}:${VER} .
 docker run -it --rm ${NAME}:${VER}
 docker rmi ${NAME}:${VER}
+docker builder prune