add a trivy cache workflow (#622)

.github/workflows/trivy-cache.yml

@@ -0,0 +1,19 @@
+---
+name: trivy-cache-db
+
+on:
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+  schedule:
+    - cron: "0 1 * * *"      
+
+jobs:
+  trivy:
+    name: Run trivy scanner
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Trivy Cache
+        uses: ConsenSys/docs-gha/trivy-update-cache@main