update nixos release: fix app-id

Author: Mic92

.github/workflows/update-nixos-release.yml

@@ -16,7 +16,7 @@ jobs:
         uses: actions/create-github-app-token@v1
         id: app-token
         with:
-          app-id: ${{ secrets.CI_APP_ID }}
+          app-id: ${{ vars.CI_APP_ID }}
           private-key: ${{ secrets.CI_APP_PRIVATE_KEY }}
 
       - name: Find latest NixOS release