Potential fix for code scanning alert no. 29: Workflow does not contain permissions

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: FuhuXia

.github/workflows/snyk.yml

@@ -88,6 +88,8 @@ jobs:
 
   snyk-monitor:
     name: snyk monitor
+    permissions:
+      contents: read
     runs-on: ubuntu-latest
     if: github.event_name == 'push'
     steps: