Fix PyTorch index URL in workflow (#1378)

Author: WoosukKwon

.github/workflows/scripts/pytorch-install.sh

@@ -6,7 +6,7 @@ cuda_version=$3
 
 # Install torch
 $python_executable -m pip install numpy pyyaml scipy ipython mkl mkl-include ninja cython typing pandas typing-extensions dataclasses setuptools && conda clean -ya
-$python_executable -m pip install torch==${pytorch_version}+cu${cuda_version//./} --index-url https://download.pytorch.org/whl/cu${cuda_version//./}
+$python_executable -m pip install torch==${pytorch_version}+cu${cuda_version//./} --extra-index-url https://download.pytorch.org/whl/cu${cuda_version//./}
 
 # Print version information
 $python_executable --version