👷(docker) add arm64 support and upgrade CI workflow steps (#11)

* 👷(docker) add arm64 platform support for image builds

Add QEMU and Buildx setup steps to enable multi-architecture Docker
image builds for both linux/amd64 and linux/arm64 platforms.

Signed-off-by: Stephan Meijer <me@stephanmeijer.com>

* ⬆️(ci) upgrade GitHub Actions workflow steps to latest versions

Update actions/setup-node from v4 to v6 and actions/cache from v4 to v5
for improved performance, security patches, and Node.js runtime compatibility.

Signed-off-by: Stephan Meijer <me@stephanmeijer.com>

---------

Signed-off-by: Stephan Meijer <me@stephanmeijer.com>

.github/workflows/docker-hub.yml

@@ -22,6 +22,12 @@ jobs:
       -
         name: Checkout repository
         uses: actions/checkout@v6
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
       -
         name: Docker meta
         id: meta
@@ -47,6 +53,7 @@ jobs:
         with:
           context: .
           target: backend-production
+          platforms: linux/amd64,linux/arm64
           build-args: DOCKER_USER=${{ env.DOCKER_USER }}:-1000
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
@@ -58,6 +65,12 @@ jobs:
       -
         name: Checkout repository
         uses: actions/checkout@v6
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
       -
         name: Docker meta
         id: meta
@@ -84,6 +97,7 @@ jobs:
           context: .
           file: ./src/frontend/Dockerfile
           target: frontend-production
+          platforms: linux/amd64,linux/arm64
           build-args: DOCKER_USER=${{ env.DOCKER_USER }}:-1000
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}