ci: Add nightly image build

Author: sniok

.github/workflows/nightly-build.yml

@@ -0,0 +1,48 @@
+name: Nightly container build
+
+on:
+  schedule:
+    - cron: "0 0 * * *"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: headlamp-k8s/headlamp
+
+jobs:
+  push_to_registry:
+    name: Build and push nightly container image
+    runs-on: ubuntu-latest
+    permissions:
+      packages: write
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@49b3bc8e6bdd4a60e6116a5414239cba5943d3cf # v3.2.0
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@988b5a0280414f521da01fcc63a27aeeb4b104db # v3.6.1
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@465a07811f14bebb1938fbed4728c6a1ff8901fc # v2.2.0
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GHCR_IMAGES }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@0a97817b6ade9f46837855d676c4cca3a2471fc9 # v4.2.1
+        with:
+          context: .
+          push: true
+          pull: true
+          platforms: linux/amd64,linux/arm64
+          tags: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:nightly
+          provenance: true
+          cache-from: type=gha
+          cache-to: type=gha,mode=max