Make it multi arch and add a publish workflow

.github/workflows/doctum.yml

@@ -1,11 +1,15 @@
 name: build doctum docs
+
+permissions:
+    contents: read
+
 on: [push]
 
 jobs:
     build:
         runs-on: ubuntu-latest
         steps:
-            - uses: actions/checkout@v3
+            - uses: actions/checkout@v4
             - name: build doctum docs
               uses: sudo-bot/action-doctum@latest
               with:

.github/workflows/publish.yml

@@ -0,0 +1,28 @@
+name: Publish Docker image
+
+permissions:
+    contents: read
+
+on:
+    push:
+        tags:
+            - "latest"
+
+jobs:
+    push_to_registry:
+        name: Push Docker image to Docker hub
+        runs-on: ubuntu-latest
+        steps:
+            - name: Check out the repository
+              uses: actions/checkout@v4
+            - name: Login to DockerHub
+              uses: docker/login-action@v2
+              with:
+                  registry: docker.io
+                  username: ${{ secrets.DOCKER_REPOSITORY_LOGIN }}
+                  password: ${{ secrets.DOCKER_REPOSITORY_PASSWORD }}
+            - name: Build action image
+              run: make docker-build
+              env:
+                  IMAGE_TAG: "docker.io/botsudo/action-doctum:latest"
+                  PLATFORM: "linux/amd64,linux/arm64/v8,linux/ppc64le,linux/s390x,linux/386,linux/arm/v7,linux/arm/v6"

Makefile

@@ -1,9 +1,26 @@
-.PHONY: update-tags docker-build
+IMAGE_TAG ?= action-doctum
+
+# All: linux/amd64,linux/arm64/v8,linux/riscv64,linux/ppc64le,linux/s390x,linux/386,linux/mips64le,linux/mips64,linux/arm/v7,linux/arm/v6
+PLATFORM ?= linux/amd64
+
+ACTION ?= load
+PROGRESS_MODE ?= plain
+
+.PHONY: update-tags update-branches push-branches docker-build docker-push
 
 docker-build:
-	docker build ./docker \
+	# https://github.com/docker/buildx#building
+	docker buildx build \
+		--tag $(IMAGE_TAG) \
+		--progress $(PROGRESS_MODE) \
+		--platform $(PLATFORM) \
 		--build-arg VCS_REF=`git rev-parse HEAD` \
-		--build-arg BUILD_DATE=`date -u +"%Y-%m-%dT%H:%M:%SZ"`
+		--build-arg BUILD_DATE=`date -u +"%Y-%m-%dT%H:%M:%SZ"` \
+		--$(ACTION) \
+		./docker
+
+docker-push:
+	docker push $(IMAGE_TAG)
 
 update-tags:
 	git checkout 5.x