automate multiarch build

Author: seanauff

.github/workflows/build-multiarch.yml

@@ -0,0 +1,45 @@
+name: Build and Push Multiarch Image to GHCR
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write  # Required for GHCR push
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: all
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push multiarch image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm/v7,linux/arm64
+          push: ${{ github.event_name != 'pull_request' }}  # Only push on push, not PR
+          tags: |
+            ghcr.io/${{ github.repository }}:latest
+            ghcr.io/${{ github.repository }}:${{ github.sha }}