Update Makefile (#508)

Makefile

@@ -195,7 +195,7 @@ build/%: ## build the latest image
 	# End repo with exactly one trailing slash, unless it is empty
 	REPO=$$(echo "$(REPO)" | sed 's:/*$$:/:' | sed 's:^\s*/*\s*$$::') &&\
 	IMAGE_NAME="$${REPO}$(notdir $@):$(TAG)" && \
-	docker build $(DARGS) --rm --force-rm -t $$IMAGE_NAME ./output/$(notdir $@) && \
+	DOCKER_BUILDKIT=0 docker build $(DARGS) --rm --force-rm -t $$IMAGE_NAME ./output/$(notdir $@) && \
 	echo -n "Built image $$IMAGE_NAME of size: " && \
 	docker images $$IMAGE_NAME --format "{{.Size}}" && \
 	echo "::set-output name=full_image_name::$$IMAGE_NAME" && \