Fix secret

.github/workflows/download_pgo.yml

@@ -8,6 +8,8 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       contents: write
+    env:
+      PGO_MERGE: ${{ secrets.PGO_MERGE }}
     steps:
       - uses: actions/checkout@v3
       - name: "Download new pgo_media_repo.pprof"