fix permission on track gh action example

Author: ruyadorno

.github/workflows/fork_pr_benchmarks_track.yml

@@ -9,6 +9,8 @@ jobs:
   track_fork_pr_branch:
     if: github.event.workflow_run.conclusion == 'success'
     runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
     env:
       BENCHMARK_RESULTS: benchmark_results.json
       PR_EVENT: event.json