Move Trivy image scan to a scheduled workflow (#267)

.github/workflows/msbuild.yml

@@ -55,14 +55,4 @@ jobs:
           context: .
           load: true
           tags: pxwebapi:${{ github.sha }}
-      - name: Run Trivy vulnerability scanner
-        uses: aquasecurity/[email protected]
-        with:
-          scan-type: image
-          image-ref: pxwebapi:${{ github.sha }}
-          format: sarif
-          output: trivy-results.sarif
-      - name: Upload Trivy scan results to GitHub Security tab
-        uses: github/codeql-action/upload-sarif@v3
-        with:
-          sarif_file: trivy-results.sarif
+

.github/workflows/trivy.yml

@@ -0,0 +1,48 @@
+name: Trivy Image Scan
+on:
+  push:
+    branches: ["main"]
+  workflow_dispatch:
+  schedule:
+    - cron: "5 11 * * 0"
+
+permissions:
+  contents: read
+
+jobs:
+  docker:
+    permissions:
+      contents: read
+      security-events: write
+      actions: read
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          load: true
+          tags: pxwebapi:${{ github.sha }}
+
+      - name: Run Trivy vulnerability scanner
+        uses: aquasecurity/[email protected]
+        with:
+          scan-type: image
+          image-ref: pxwebapi:${{ github.sha }}
+          format: sarif
+          output: trivy-results.sarif
+
+      - name: Upload Trivy scan results to GitHub Security tab
+        uses: github/codeql-action/upload-sarif@v3
+        with:
+          sarif_file: trivy-results.sarif