Erdantic

This will be the last version that supports Python 3.7.

- Added version typer version ceiling of `< 0.10.0` due to incompatibility with a fix introduced in that version.

- Added support for Pydantic V1 legacy models. These are models created from the `pydantic.v1` namespace when Pydantic V2 is installed. ([PR 94](https://github.com/drivendataorg/erdantic/pull/94) from [ursereg](https://github.com/ursereg))

- Added support for Pydantic V2.
- Removed support for Pydantic V1.
- Changed the init signature for `PydanticField` to work with Pydantic V2's API.
- Added `is_many` and `is_nullable` functions to `erdantic.typing`.

- Changed Pydantic dependency to be `< 2`. This will be the final version of erdantic that supports Pydantic V1.
- Changed to pyproject.toml-based build.

- Removed support for Python 3.6. ([Issue 51](https://github.com/drivendataorg/erdantic/issues/51), [PR #56](https://github.com/drivendataorg/erdantic/pull/56))
- Added support for modules as inputs to all entrypoints to diagram creation (`create`, `draw`, `to_dot`, CLI). For all modules passed, erdantic will find all supported data model classes in each module. ([Issue 23](https://github.com/drivendataorg/erdantic/issues/23), [PR #58](https://github.com/drivendataorg/erdantic/pull/58))
- Added new parameter `limit_search_models_to` to all entrypoints to allow for limiting which data model classes will be yielded from searching a module.

- Fixed error when rendering a data model that has field using `typing.Literal`. ([PR 49](https://github.com/drivendataorg/erdantic/pull/49))