installer is not requesting packaging but the code requires it in practice
Labels: name: auto:bug, name: area: models

### System Info

I am using langchain==0.0.283 and openai==0.28.0.
There seems to be no mention to packaging as a dependency, but when I run my system under a docker image from python:3.10.12-slim as basis, packaging is missing.
So please add it explicitely as a dependency, such as packaging==21.3.
Thanks.

### Who can help?

_No response_

### Information

- [ ] The official example notebooks/scripts
- [ ] My own modified scripts

### Related Components

- [ ] LLMs/Chat Models
- [ ] Embedding Models
- [ ] Prompts / Prompt Templates / Prompt Selectors
- [ ] Output Parsers
- [ ] Document Loaders
- [ ] Vector Stores / Retrievers
- [ ] Memory
- [ ] Agents / Agent Executors
- [ ] Tools / Toolkits
- [ ] Chains
- [ ] Callbacks/Tracing
- [ ] Async

### Reproduction

1. install langchain as a dependency, such as langchain==0.0.283
2. run the code in a container environment such as: FROM python:3.10.12-slim
3. you will get runtime errors

### Expected behavior

runtime errors happening:

  File "main/routes_bot.py", line 4, in init main.routes_bot
  File "/usr/local/lib/python3.10/site-packages/langchain/__init__.py", line 6, in <module>
    from langchain.agents import MRKLChain, ReActChain, SelfAskWithSearchChain
  File "/usr/local/lib/python3.10/site-packages/langchain/agents/__init__.py", line 31, in <module>
    from langchain.agents.agent import (
  File "/usr/local/lib/python3.10/site-packages/langchain/agents/agent.py", line 14, in <module>
    from langchain.agents.agent_iterator import AgentExecutorIterator
  File "/usr/local/lib/python3.10/site-packages/langchain/agents/agent_iterator.py", line 21, in <module>
    from langchain.callbacks.manager import (
  File "/usr/local/lib/python3.10/site-packages/langchain/callbacks/__init__.py", line 10, in <module>
    from langchain.callbacks.aim_callback import AimCallbackHandler
  File "/usr/local/lib/python3.10/site-packages/langchain/callbacks/aim_callback.py", line 5, in <module>
    from langchain.schema import AgentAction, AgentFinish, LLMResult
  File "/usr/local/lib/python3.10/site-packages/langchain/schema/__init__.py", line 28, in <module>
    from langchain.schema.output_parser import (
  File "/usr/local/lib/python3.10/site-packages/langchain/schema/output_parser.py", line 21, in <module>
    from langchain.schema.runnable import Runnable, RunnableConfig
  File "/usr/local/lib/python3.10/site-packages/langchain/schema/runnable/__init__.py", line 1, in <module>
    from langchain.schema.runnable._locals import GetLocalVar, PutLocalVar
  File "/usr/local/lib/python3.10/site-packages/langchain/schema/runnable/_locals.py", line 15, in <module>
    from langchain.schema.runnable.base import Input, Output, Runnable
  File "/usr/local/lib/python3.10/site-packages/langchain/schema/runnable/base.py", line 58, in <module>
    from langchain.utils.aiter import atee, py_anext
  File "/usr/local/lib/python3.10/site-packages/langchain/utils/__init__.py", line 17, in <module>
    from langchain.utils.utils import (
  File "/usr/local/lib/python3.10/site-packages/langchain/utils/utils.py", line 9, in <module>
    from packaging.version import parse
ModuleNotFoundError: No module named 'packaging'