update navsim v1.1 reliance

Author: WCJ-BERT

docs/installation.md

@@ -191,14 +191,19 @@ pip install shapely==2.0.4
 
 #### 6. Set Environment Variables
 
+Also, we rely on NAVSIM devkit, please git clone and switch to `v1.1` branch:
+```bash
+git clone -b v1.1 https://github.com/autonomousvision/navsim.git
+```
 Add to your `~/.bashrc` or `~/.zshrc`:
 
 ```bash
 # AlgEngine Environment Variables
 export WORLDENGINE_ROOT="/path/to/WorldEngine"
 export ALGENGINE_ROOT="${WORLDENGINE_ROOT}/projects/AlgEngine"
 export NUPLAN_MAPS_ROOT="${WORLDENGINE_ROOT}/data/raw/nuplan/maps"
-export PYTHONPATH=$WORLDENGINE_ROOT:$ALGENGINE_ROOT:$PYTHONPATH
+export NAVSIM_DEVKIT_ROOT="/path/to/your/navsim/v1.1"
+export PYTHONPATH=$WORLDENGINE_ROOT:$ALGENGINE_ROOT:$NAVSIM_DEVKIT_ROOT:$PYTHONPATH
 ```
 
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