Update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/copilot-setup-steps.yml

@@ -18,7 +18,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - uses: actions/setup-node@v5
+      - uses: actions/setup-node@v6
         with:
           node-version: "24"