ci: replace vulnerability scanning workflow with Trivy integration (#4421)

- Remove the vulnerability-scanning job from the gin workflow
- Add a dedicated Trivy security scan workflow with scheduled, push, pull request, and manual triggers
- Improve Trivy scan output by uploading SARIF results to the GitHub Security tab and logging table output

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

.github/workflows/gin.yml

@@ -81,19 +81,3 @@ jobs:
         uses: codecov/codecov-action@v5
         with:
           flags: ${{ matrix.os }},go-${{ matrix.go }},${{ matrix.test-tags }}
-
-  vulnerability-scanning:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v5
-        with:
-          fetch-depth: 0
-
-      - name: Run Trivy vulnerability scanner in repo mode
-        uses: aquasecurity/trivy-action@0.33.1
-        with:
-          scan-type: "fs"
-          ignore-unfixed: true
-          format: "table"
-          exit-code: "1"
-          severity: "CRITICAL,HIGH,MEDIUM"

.github/workflows/trivy-scan.yml

@@ -0,0 +1,57 @@
+name: Trivy Security Scan
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+  schedule:
+    # Run every 3 months (quarterly) on the 1st day at 00:00 UTC
+    # Months: January (1), April (4), July (7), October (10)
+    - cron: '0 0 1 1,4,7,10 *'
+  workflow_dispatch: # Allow manual trigger
+
+permissions:
+  contents: read
+  security-events: write # Required for uploading SARIF results
+
+jobs:
+  trivy-scan:
+    name: Trivy Security Scan
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 0
+
+      - name: Run Trivy vulnerability scanner (source code)
+        uses: aquasecurity/trivy-action@0.33.1
+        with:
+          scan-type: 'fs'
+          scan-ref: '.'
+          scanners: 'vuln,secret,misconfig'
+          format: 'sarif'
+          output: 'trivy-results.sarif'
+          severity: 'CRITICAL,HIGH,MEDIUM'
+          ignore-unfixed: true
+
+      - name: Upload Trivy results to GitHub Security tab
+        uses: github/codeql-action/upload-sarif@v3
+        if: always()
+        with:
+          sarif_file: 'trivy-results.sarif'
+
+      - name: Run Trivy scanner (table output for logs)
+        uses: aquasecurity/trivy-action@0.33.1
+        if: always()
+        with:
+          scan-type: 'fs'
+          scan-ref: '.'
+          scanners: 'vuln,secret,misconfig'
+          format: 'table'
+          severity: 'CRITICAL,HIGH,MEDIUM'
+          ignore-unfixed: true
+          exit-code: '1'