use ko instead for simplicity

Author: sharifelgamal

Makefile

@@ -1,17 +1,12 @@
 REGISTRY?=gcr.io/k8s-minikube
-VERSION=v0.0.3
+VERSION=20210202-test2
+GOOS?=$(shell go env GOOS)
 
 build: ## Build the gcp-auth-webhook binary
-	CGO_ENABLED=0 GOOS=linux go build -o out/gcp-auth-webhook -ldflags=$(PROVISIONER_LDFLAGS) server.go
+	CGO_ENABLED=0 GOOS=linux go build -o out/gcp-auth-webhook server.go
 
 .PHONY: image
-image: build ## Create the multiarch manifest builder
-	env DOCKER_CLI_EXPERIMENTAL=enabled docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
-	env DOCKER_CLI_EXPERIMENTAL=enabled docker buildx rm --builder gcp-auth-builder || true
-	env DOCKER_CLI_EXPERIMENTAL=enabled docker buildx create --name gcp-auth-builder --use
-
-
-.PHONY: push
-push: image ## Push the manifest and images up to the registry
-	env DOCKER_CLI_EXPERIMENTAL=enabled docker buildx build --platform linux/arm64,linux/amd64 -t $(REGISTRY)/gcp-auth-webhook:$(VERSION) --push -f Dockerfile ./out
-
+image: build ## Create and push multiarch manifest and images
+	curl -L https://github.com/google/ko/releases/download/v0.8.0/ko_0.8.0_$(GOOS)_x86_64.tar.gz | tar xzf - ko && chmod +x ./ko
+	KO_DOCKER_REPO=$(REGISTRY) ./ko publish -B . --platform all -t $(VERSION)
+	rm ./ko