build: :arrow_up: Updating to `pydantic v2.0.0` (#863)
* build: :arrow_up: Updating to `pydantic v2.0.0`
Fixes #862
* ci: :arrow_up: Update pydantic
* refactor: :construction: Apply new data types
See also:
- https://docs.pydantic.dev/dev-v2/migration/#code-transformation-tool
- https://github.com/pydantic/pydantic/issues/6024#issue-1744184812
* refactor: :recycle: remove duplicated `@classmethod`
* fix: :rotating_light: Add type of `Any` for py 3.8
- Unfortunately, `model_config = ConfigDict(arbitrary_types_allowed=True)` wasn't working out for type of `numpy` for Python 3.8
