Add GHA workflow to publish db-sync image

.github/workflows/build-sync-latest.yml

@@ -0,0 +1,43 @@
+---
+name: Build Lauth database sync
+#description: Builds an image to synchronize databases
+
+on:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build image and push to GitHub Container Registry
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: 'ghcr.io/mlibrary/lauth/db-sync:${{ github.sha }}, ghcr.io/mlibrary/lauth/db-sync:latest'
+          file: db/sync/Dockerfile
+          platforms: linux/amd64, linux/arm64
+
+      - name: Image digest
+        run: |
+          echo '${{ steps.docker_build.outputs.digest }}'
+