chore(Makefile): download ko as a binary

Author: weisdd

Toolchain.mk

@@ -121,8 +121,12 @@ ifeq (, $(shell which $(KO)))
 	$(info $(M) installing ko)
 	@{ \
 	set -e ;\
-	GOBIN=$(BIN) go install github.com/google/ko@$(KO_VERSION) ;\
-	mv $(BIN)/ko $(KO) ;\
+	OSTYPE=$(shell uname | awk '{print $$0}') && ARCH=$(shell go env GOARCH) && \
+	curl -sSLo $(KO).tar.gz https://github.com/ko-build/ko/releases/download/$(KO_VERSION)/ko_$${OSTYPE}_$${ARCH}.tar.gz && \
+	tar -zxvf $(KO).tar.gz ko && \
+	chmod +x ko && \
+	mv ko $(KO) && \
+	rm $(KO).tar.gz ;\
 	}
 endif