Package is missing library stubs or py.typed marker

## Problem

When deriving a CrateDB adapter for LangChain from [langchain-postgres](https://github.com/langchain-ai/langchain-postgres), we are observing this error when invoking `make lint`.

```
langchain_cratedb/cratedb/model.py:16: error: Skipping analyzing "sqlalchemy_cratedb": module is installed, but missing library stubs or py.typed marker [import-untyped]
```

## Workaround
For your `pyproject.toml`.
```toml
[tool.mypy]
ignore_missing_imports = "True"
```

Start by inspecting pyproject.toml and the package configuration related to the sqlalchemy_cratedb distribution. Run the repository's make lint command, then verify that the consuming langchain_cratedb/model.py import is analyzed without the missing-stubs or py.typed warning.

Written by the indexing model from the issue text.