Run benchmarks every 12 hours

.github/workflows/benchmark.yml

@@ -9,11 +9,13 @@ on:
       - main
       - '[0-9]+.[0-9]+.x'
   pull_request:
+  schedule:
+    - cron: '0 */12 * * *'
 
 jobs:
   linux:
     runs-on: ubuntu-latest-8-cores
-    if: ${{ github.repository == 'signalapp/Signal-Desktop-Private' }}
+    if: ${{ github.repository == 'signalapp/Signal-Desktop-Private' && (!github.event.schedule || github.ref == 'refs/heads/main') }}
     timeout-minutes: 30
 
     steps: