Update benchmarks.yml

Author: juliagmt-google

.github/workflows/benchmarks.yml

@@ -4,6 +4,9 @@ on:
   pull_request:
     branches:
       - main
+  workflow_dispatch:  # Allows manual triggering
+  schedule:
+    - cron: '0 */6 * * *'  # Run every 6 hours (at minute 0 of hours 0, 6, 12, 18)
   # workflow_dispatch:
   #   inputs:
   #     halt-for-connection: