pin the gpt-fast repo commit version (#2966)

Author: agunapal

examples/large_models/gpt_fast/README.md

@@ -23,11 +23,17 @@ The examples has been tested on A10, A100 as well as H100.
 Install dependencies and upgrade torch to nightly build (currently required)
 ```
 git clone https://github.com/pytorch-labs/gpt-fast/
+git checkout f44ef4eb55b54ec4c452b669eee409421adabd60
 pip install sentencepiece huggingface_hub
 pip uninstall torchtext torchdata torch torchvision torchaudio -y
 pip install --pre torch torchvision torchaudio --index-url https://download.pytorch.org/whl/nightly/cu121 --ignore-installed
 ```
 
+You can also install PyTorch nightlies using the below command
+```
+python ./ts_scripts/install_dependencies.py --cuda=cu121 --nightly_torch
+```
+
 ### Step 1: Download  and convert the weights
 
 Currently supported models: