Merge pull request #41 from takama/hotfix/certs_alpine_image

Fixed #40 alpine image for installing certificates

Makefile

@@ -53,7 +53,7 @@ build: vendor test certs
 certs:
 ifeq ("$(wildcard $(CA_DIR)/ca-certificates.crt)","")
 	@echo "+ $@"
-	@docker run --name ${CONTAINER_NAME}-certs -d alpine:edge sh -c "apk --update upgrade && apk add ca-certificates && update-ca-certificates"
+	@docker run --name ${CONTAINER_NAME}-certs -d alpine:latest sh -c "apk --update upgrade && apk add ca-certificates && update-ca-certificates"
 	@docker wait ${CONTAINER_NAME}-certs
 	@mkdir -p ${CA_DIR}
 	@docker cp ${CONTAINER_NAME}-certs:/etc/ssl/certs/ca-certificates.crt ${CA_DIR}