Add dev container smoke test to CI

Author: garryod

.github/workflows/devcontainer.yml

@@ -0,0 +1,28 @@
+name: Dev Container CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    # pull requests are a duplicate of a branch push if within the same repo.
+    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.repository
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        directory:
+          - "."
+          - "backend"
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4.0.0
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3.0.0
+
+      - name: Build dev container
+        uses: devcontainers/ci@v0.3.1900000329
+        with:
+          subFolder: ${{ matrix.directory }}