ci: run trivy scan on container image

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

.github/workflows/docker.yaml

@@ -92,3 +92,18 @@ jobs:
             org.opencontainers.image.revision=${{ github.sha }}
             org.opencontainers.image.licenses=${{ github.event.repository.license.spdx_id }}
             org.opencontainers.image.documentation=https://dexidp.io/docs/
+
+      - name: Run Trivy vulnerability scanner
+        uses: aquasecurity/trivy-action@0.2.1
+        with:
+          image-ref: "ghcr.io/dexidp/dex:${{ steps.tags.outputs.version }}"
+          format: "template"
+          template: "@/contrib/sarif.tpl"
+          output: "trivy-results.sarif"
+        if: github.event_name == 'push'
+
+      - name: Upload Trivy scan results to GitHub Security tab
+        uses: github/codeql-action/upload-sarif@v1
+        with:
+          sarif_file: "trivy-results.sarif"
+        if: github.event_name == 'push'