update readme

README.md

@@ -33,6 +33,9 @@ $ conda create --name bob.paper.iccv2023_face_ti --file package-list.txt
 # activate the environment
 $ conda activate bob.paper.iccv2023_face_ti  
 
+# install torch (required version)
+$ pip install torch==1.13.0+cu117 torchvision==0.14.0+cu117 --extra-index-url https://download.pytorch.org/whl/cu117
+
 # install paper package
 $ pip install ./ --no-build-isolation  
 ```