chore: Update nix_update.yml in tsnsrv

Author: antifuchs

.github/workflows/nix_update.yml

@@ -11,7 +11,7 @@ jobs:
       contents: write
       pull-requests: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: boinkor-net/ci-baseline-nix/actions/setup@main
         with:
           tailnet_client_id: ${{ secrets.TAILSCALE_CI_CLIENT_ID }}