LangServe examples need to be updated

[scottslowe]

The OpenAI LangChain libraries have changed locations and the examples need to be updated appropriately. AFAICT, the following changes need to be made:

• Line 3 of app/server.py needs to be changed to from langchain_openai import ChatOpenAI
• The [tool.poetry.dependencies] section of pyproject.toml needs to have langchain-openai = "^0.0.5" added
• The poetry.lock file needs to be updated with poetry lock (else container builds will fail)

These changes need to be applied to all language variations of the the AWS LangServe examples.

[pulumi-bot]

Cannot close issue:

• does not have required labels: resolution/

Please fix these problems and try again.