Update instructions.

README.md

@@ -26,7 +26,7 @@ pip install numpy scipy
 pip install torch --index-url https://download.pytorch.org/whl/cpu
 
 # add it to the Jupyter Lab in Maxwell
-pip install ipykernel
+pip install ipykernel jupyter
 python -m ipykernel install --name pes_to_spec_env
 
 ```