Update introduction_en.ipynb (#5653)

modelcenter/PP-HelixFold/introduction_en.ipynb

@@ -49,7 +49,7 @@
     "We provide a script `setup_env` that setup a `conda` environment and installs all dependencies. You can change the name of the environment and CUDA version in `setup_env`. Run:\n",
     "```bash\n",
     "git clone https://github.com/PaddlePaddle/PaddleHelix.git # download PaddleHelix\n",
-    "cd https://github.com/PaddlePaddle/PaddleHelix/tree/dev/apps/protein_folding/helixfold\n",
+    "cd /apps/protein_folding/helixfold\n",
     "wget https://paddle-wheel.bj.bcebos.com/develop/linux/linux-gpu-cuda11.2-cudnn8-mkl-gcc8.2-avx/paddlepaddle_gpu-0.0.0.post112-cp37-cp37m-linux_x86_64.whl\n",
     "sh setup_env\n",
     "conda activate helixfold # activate the conda environment\n",