ref(Makefile): use gen-changelog.sh from go-dev

Author: mboersma

Makefile

@@ -7,7 +7,7 @@ export GO15VENDOREXPERIMENT=1
 
 # dockerized development environment variables
 REPO_PATH := github.com/deis/${SHORT_NAME}
-DEV_ENV_IMAGE := quay.io/deis/go-dev:0.11.1
+DEV_ENV_IMAGE := quay.io/deis/go-dev:0.12.0
 DEV_ENV_WORK_DIR := /go/src/${REPO_PATH}
 DEV_ENV_PREFIX := docker run --rm -e GO15VENDOREXPERIMENT=1 -v ${CURDIR}:${DEV_ENV_WORK_DIR} -w ${DEV_ENV_WORK_DIR}
 DEV_ENV_CMD := ${DEV_ENV_PREFIX} ${DEV_ENV_IMAGE}
@@ -42,6 +42,10 @@ build:
 test:
 	${DEV_ENV_CMD} sh -c 'go test $$(glide nv)'
 
+update-changelog:
+	${DEV_ENV_PREFIX} -e RELEASE=${DEIS_RELEASE} ${DEV_ENV_IMAGE} gen-changelog.sh \
+	  | cat - CHANGELOG.md > tmp && mv tmp CHANGELOG.md
+
 docker-build: build
 	docker build --rm -t ${IMAGE} rootfs
 	docker tag -f ${IMAGE} ${MUTABLE_IMAGE}