chore: docker build workflow

.github/workflows/docker.yaml

@@ -0,0 +1,18 @@
+name: Docker build
+on:
+  push:
+    branches: [ main ]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - uses: docker/setup-qemu-action@v1
+      - uses: docker/setup-buildx-action@v1
+      - name: Build the Docker image
+        run: docker buildx build -t ghcr.io/${{ github.repository_owner }}/snort:latest --platform linux/amd64,linux/arm64 --push .