Codespaces and devcontainer was broken by the [repo
restructure](https://github.com/langchain-ai/langchain/discussions/8043).
- Description: Add libs/langchain to container so it can be built
without error.
- Issue: -
- Dependencies: -
- Tag maintainer: @hwchase17 @baskaryan
- Twitter handle: @finnless
The failed build log says:
```
#10 [langchain-dev-dependencies 2/2] RUN poetry install --no-interaction --no-ansi --with dev,test,docs
#10 sha256:e850ee99fc966158bfd2d85e82b7c57244f47ecbb1462e75bd83b981a56a1929
2023-07-23 23:30:33.692Z: #10 0.827
#10 0.827 Directory libs/langchain does not exist
2023-07-23 23:30:33.738Z: #10 ERROR: executor failed running [/bin/sh -c poetry install --no-interaction --no-ansi --with dev,test,docs]: exit code: 1
```
The new pyproject.toml imports from libs/langchain:
77bf75c236/pyproject.toml (L14-L16)
But libs/langchain is never added to the dev.Dockerfile:
77bf75c236/libs/langchain/dev.Dockerfile (L37-L39)
* Adopts [Poetry](https://python-poetry.org/) as a dependency manager
* Introduces dependency version requirements
* Deprecates Python 3.7 support
**TODO**
- [x] Update developer guide
- [x] Add back `playwright`, `manifest-ml`, and `jupyter` to dependency
group
**Not Doing => Fast Follow**
- Investigate single source for version, perhaps relying on GitHub tags
and [tackling this
issue](https://github.com/hwchase17/langchain/issues/26)
