ci: add the Scorecard workflow

.github/workflows/scorecard.yml

@@ -0,0 +1,39 @@
+name: Scorecard
+
+# No push trigger: the weekly run on main publishes the results, so rescanning
+# after every merge only repeated it.
+on:
+  branch_protection_rule:
+  schedule:
+    - cron: "35 6 * * 1"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  analysis:
+    name: Scorecard analysis
+    timeout-minutes: 15
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write # Upload Scorecard results to code scanning.
+      id-token: write # Publish results for the public Scorecard badge.
+    steps:
+      - name: Check out source
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Run Scorecard
+        uses: ossf/scorecard-action@fa7117db83c52d787ae5a89f350999701505d78e # v2.5.0
+        with:
+          results_file: results.sarif
+          results_format: sarif
+          publish_results: true
+
+      - name: Upload results to code scanning
+        uses: github/codeql-action/upload-sarif@6f2ac81f5cd81fe351a197ba0b00d91d03cd2aee # v4.39.0
+        with:
+          sarif_file: results.sarif