remove duplicated timestamp

Makefile

@@ -121,11 +121,11 @@ publish:
 
 #Update README.md based on the template ._README.md
 TOOLSET := `echo "$(sort $(IMAGES_TO_PUBLISH))" | sed -e "s/ /\n - /g"))`
-README_HEAD = `cat ./_README.md | sed -e 's/%CONTAINERS_LIST%.*//g'`
+README_HEAD = `cat ./_README.md | sed -e '/%CONTAINERS_LIST%/Q'`
 README_TAIL = `cat ./_README.md | sed -e '1,/%CONTAINERS_LIST%/d'`
 
 update_readme:
-	@echo "$(README_HEAD)\n - $(TOOLSET) $(README_TAIL)" | sed -e "0,/RE/s/%LAST_UPDATE%/\n_Last update: `date`_ \n/" > README.md
+	@echo "$(README_HEAD)  \n\n - $(TOOLSET)  \n$(README_TAIL)" | sed -e "0,/RE/s/%LAST_UPDATE%/\n_Last update: `date`_ \n/" > README.md
 
 delete_dangling_images:
 	@echo "Removing dangling images"