Bump langchain version + add required pck to run

[gtracer]

No description provided.

[shynsky]

Tested, works as expected.

[arnegebert]

Edit: same issue as langchain-ai/langchain#1100, I created my embeddings with an older version

Trying to upgrade this PR to the latest version, I receive the following error:

Traceback (most recent call last):
  File "/home/arne/Documents/GitHub/cashew/qa.py", line 25, in <module>
    result = chain({"question": args.question})
  File "/home/arne/.local/share/virtualenvs/cashew-KA6SwOM3/lib/python3.10/site-packages/langchain/chains/base.py", line 142, in __call__
    raise e
  File "/home/arne/.local/share/virtualenvs/cashew-KA6SwOM3/lib/python3.10/site-packages/langchain/chains/base.py", line 139, in __call__
    outputs = self._call(inputs)
  File "/home/arne/.local/share/virtualenvs/cashew-KA6SwOM3/lib/python3.10/site-packages/langchain/chains/qa_with_sources/base.py", line 105, in _call
    docs = self._get_docs(inputs)
  File "/home/arne/.local/share/virtualenvs/cashew-KA6SwOM3/lib/python3.10/site-packages/langchain/chains/qa_with_sources/vector_db.py", line 49, in _get_docs
    docs = self.vectorstore.similarity_search(
  File "/home/arne/.local/share/virtualenvs/cashew-KA6SwOM3/lib/python3.10/site-packages/langchain/vectorstores/faiss.py", line 166, in similarity_search
    docs_and_scores = self.similarity_search_with_score(query, k)
  File "/home/arne/.local/share/virtualenvs/cashew-KA6SwOM3/lib/python3.10/site-packages/langchain/vectorstores/faiss.py", line 135, in similarity_search_with_score
    embedding = self.embedding_function(query)
  File "/home/arne/.local/share/virtualenvs/cashew-KA6SwOM3/lib/python3.10/site-packages/langchain/embeddings/openai.py", line 167, in embed_query
    embedding = self._embedding_func(text, engine=self.query_model_name)
  File "/home/arne/.local/share/virtualenvs/cashew-KA6SwOM3/lib/python3.10/site-packages/langchain/embeddings/openai.py", line 123, in _embedding_func
    if self.embedding_ctx_length > 0:
AttributeError: 'OpenAIEmbeddings' object has no attribute 'embedding_ctx_length'

Does someone know what is going on here? Obviously a version mismatch, but not sure where. (I tried with 0.0.100 and 0.0.123.)

[JackCrish]

Tested. Works. Just re-export your API key when finished installing. Thank you.