Update regression_test.yml

Author: amdfaa

.github/workflows/regression_test.yml

@@ -35,6 +35,7 @@ jobs:
             gpu-arch-version: ""
           - name: ROCM Nightly
             runs-on: linux.rocm.gpu.torchao
+            if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}
             torch-spec: '--pre torch --index-url https://download.pytorch.org/whl/nightly/rocm6.3'
             gpu-arch-type: "rocm"
             gpu-arch-version: "6.3"