Add missing -e

DEVELOPING.md

@@ -41,7 +41,7 @@ python3 -m pip install -e "./[dev,torch]"
 ```
 
 Note: Running all pytorch tests using `make test TARGETS=torch`, also requires `torchvision`
-and `onnxruntime` install all these dependencies using `python3 -m pip install "./[dev, torch, torchvision, onnxruntime]"`
+and `onnxruntime` install all these dependencies using `python3 -m pip install -e "./[dev, torch, torchvision, onnxruntime]"`
 
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