add GitHub actions workflow

.github/workflows/ghcr.yml

@@ -0,0 +1,33 @@
+name: Build & Publish (main)
+on:
+  push:
+    branches: [ main ]
+    tags:
+      - "*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Log into container registry
+        uses: docker/#-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ github.token }}
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+      - name: Build Docker image
+        uses: docker/build-push-action@v6
+        with:
+          push: true
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}