Switched to latest Docker buildx github action

.github/workflows/build-multiarch.yml

@@ -4,6 +4,7 @@ on:
     branches:
       - multiarch
       - multiarch-latest
+      - "test-multiarch-.*"
     tags:
       - "[0-9]+.[0-9]+.[0-9]+-multiarch"
       - "[0-9]+.[0-9]+.[0-9]+-multiarch-latest"
@@ -14,14 +15,48 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v2.2.0
-      - name: Get branch name
-        uses: nelonoel/branch-name@v1
-      - name:  Docker Buildx
-        uses: ilteoood/docker_buildx@1.0.4
-        with:
-          publish: true
-          imageName: itzg/minecraft-server
-          tag: ${{ env.BRANCH_NAME }}
-          dockerHubUser: ${{ secrets.DOCKER_USER }}
-          dockerHubPassword: ${{ secrets.DOCKER_PASSWORD }}
 
+      - name: Prepare
+        id: prep
+        run: |
+          DOCKER_IMAGE=itzg/minecraft-server
+          VERSION=edge
+          if [[ $GITHUB_REF == refs/tags/* ]]; then
+            VERSION=${GITHUB_REF#refs/tags/v}
+          fi
+          if [[ $GITHUB_REF == refs/heads/* ]]; then
+            VERSION=${GITHUB_REF#refs/heads/}
+            if [[ $VERSION == master ]]; then
+              VERSION=latest
+            fi
+          fi
+          TAGS="${DOCKER_IMAGE}:${VERSION}"
+          echo ::set-output name=tags::${TAGS}
+          echo ::set-output name=cache_from::${TAGS}
+
+      - name: Setup Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_USER }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Build and push
+        id: docker_build
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          file: ./Dockerfile
+          platforms: linux/amd64,linux/arm/v7,linux/arm64
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.prep.outputs.tags }}
+          cache-from: type=registry,ref=${{ steps.prep.outputs.cache_from }}
+          cache-to: type=inline
+
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}