ci: Also exempt 'security' tag from auto-close (ggml-org#21844)

Author: ckastner

.github/workflows/close-issue.yml

@@ -17,7 +17,7 @@ jobs:
     steps:
       - uses: actions/stale@v10
         with:
-          exempt-issue-labels: "refactoring,help wanted,good first issue,research 🔬,bug,roadmap"
+          exempt-issue-labels: "refactoring,help wanted,good first issue,research 🔬,bug,roadmap,security"
           days-before-issue-stale: 30
           days-before-issue-close: 14
           stale-issue-label: "stale"