Use gitea/gitea-base as base

and replace deprecated MAINTAINER by LABEL (https://docs.docker.com/engine/reference/builder/#maintainer-deprecated)

Dockerfile

@@ -1,5 +1,5 @@
-FROM alpine:3.5
-MAINTAINER Thomas Boerger <thomas@webhippie.de>
+FROM gitea/gitea-base
+LABEL maintainer "Thomas Boerger <thomas@webhippie.de>"
 
 EXPOSE 22 3000
 

Makefile

@@ -198,14 +198,14 @@ docker:
 	docker build -t $(DOCKER_REF) .
 
 .PHONY: docker-multi-arch-push-manifest
-docker-multi-arch-push-manifest: DOCKER_MANIFEST ?= docker/manifest/base.yml #Manifest to update
+docker-multi-arch-push-manifest: DOCKER_MANIFEST ?= docker/manifest/base.yml
 docker-multi-arch-push-manifest:
 	@hash manifest-tool > /dev/null 2>&1; if [ $$? -ne 0 ]; then \
 		go get -u github.com/estesp/manifest-tool; \
 	fi
-	$(SED_INPLACE) "s;gitea/gitea;$(DOCKER_IMAGE);g" $(DOCKER_MANIFEST) #Replace if using custom image name
-	@manifest-tool --docker-cfg $HOME/.docker/ push from-spec $(DOCKER_MANIFEST) #Up new references
-	$(SED_INPLACE) "s;$(DOCKER_IMAGE);gitea/gitea;g" $(DOCKER_MANIFEST) #Revert back config
+	$(SED_INPLACE) "s;gitea/gitea;$(DOCKER_IMAGE);g" $(DOCKER_MANIFEST)
+	@manifest-tool push from-spec $(DOCKER_MANIFEST)
+	$(SED_INPLACE) "s;$(DOCKER_IMAGE);gitea/gitea;g" $(DOCKER_MANIFEST)
 
 .PHONY: release
 release: release-dirs release-windows release-linux release-darwin release-copy release-check

docker/manifest/base.yml

@@ -4,7 +4,7 @@ manifests:
     platform:
       architecture: amd64
       os: linux
-  - image:multiarch/alpine:x86-latest-stable
+  - image: multiarch/alpine:x86-latest-stable
     platform:
       architecture: 386
       os: linux