Adjust ipython requirements and example (#415)

add ipython to requirements; delete unused import from paul graham example

docs/getting_started/starter_example.md

@@ -36,7 +36,6 @@ Create a new `.py` file with the following:
 
 ```python
 from gpt_index import GPTSimpleVectorIndex, SimpleDirectoryReader
-from IPython.display import Markdown, display
 
 documents = SimpleDirectoryReader('data').load_data()
 index = GPTSimpleVectorIndex(documents)

requirements.txt

@@ -6,6 +6,7 @@ pytest-dotenv==0.5.2
 
 # third-party (libraries)
 rake_nltk==1.0.6
+ipython==8.9.0
 
 # linting stubs
 types-requests==2.28.11.8