fixup: dont use buildx for nomos image (#350)

main switched all of the docker image builds to buildx, which happened
after the 1.14 release branch was cut. We are seeing an issue with the
build of this image in CI. This is a fixup to the cherry pick
to use docker build instead.

Makefile.build

@@ -100,7 +100,7 @@ build-images: license
 		--build-arg VERSION=${VERSION} \
 		.
 	@echo "+++ Building the Nomos image: $(NOMOS_TAG)"
-	@docker buildx build $(DOCKER_BUILD_QUIET) \
+	@docker build $(DOCKER_BUILD_QUIET) \
 		--target $(NOMOS_IMAGE) \
 		-t $(NOMOS_TAG) \
 		-f build/all/Dockerfile \