Build Docker container using GH Workflows (cmu-sei#266)

* Build Docker package using Github Actions

.github/workflows/docker.yml

@@ -0,0 +1,58 @@
+name: Docker Build and Push
+
+on:
+  push:
+    branches:
+      - '*'
+  pull_request:
+  schedule:
+    - cron: '42 06 * * sat' # Run every Saturday at 06:42 UTC
+
+
+env:
+  REGISTRY: ghcr.io
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
+    - name: Login to GitHub Container Registry (GHCR)
+      uses: docker/login-action@v3
+      with:
+        registry: ${{ env.REGISTRY }}
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Extract metadata (tags, labels) for Docker
+      id: meta
+      uses: docker/metadata-action@v5
+      with:
+        images: |
+          ${{ env.REGISTRY }}/${{ github.repository }}
+
+    - name: Build and push Docker image
+      id: build-and-push
+      uses: docker/build-push-action@v5
+      with:
+        context: .
+        push: ${{ github.event_name != 'schedule' }}
+        build-args: |
+          CFLAGS=
+          NCPU=4
+        provenance: false
+        tags: ${{ steps.meta.outputs.tags }}
+        labels: ${{ steps.meta.outputs.labels }}
+        # Don't use cache for weekly builds
+        cache-from: ${{ (github.event_name != 'schedule') && 'type=gha' }}
+        cache-to: type=gha,mode=max
+
+    - name: Log Docker image digest
+      if: steps.build-and-push.outputs.pushed
+      run: echo "Docker image pushed ${{ steps.build-and-push.outputs.digest }}"