[CI] Add Trivy vulnerability scans

Adds Trivy vulnerability scan jobs to both CI and PR workflows.

Resolves #466

.github/workflows/ci-pr.yml

@@ -40,3 +40,24 @@ jobs:
           name: test-results
           path: '*/build/reports/tests/**/*.*'
           retention-days: 3
+  scan:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Run Trivy vulnerability scanner in repo mode
+        uses: aquasecurity/trivy-action@master
+        with:
+          scan-type: 'fs'
+          ignore-unfixed: true
+          format: 'table'
+          severity: 'CRITICAL,HIGH'
+      - name: 'Scanned'
+        shell: bash
+        run: echo "::info ::Scanned"
+  done:
+    runs-on: ubuntu-latest
+    needs: [ build_and_verify, scan ]
+    steps:
+      - name: 'Done'
+        shell: bash
+        run: echo "::info ::Done"