Add pydantic<2 into the pyproject.toml file

Related to the [PR#215](https://github.com/project-codeflare/codeflare-sdk/pull/215). pydantic<2 should be added the [pyproject.toml](https://github.com/project-codeflare/codeflare-sdk/blob/0d9b23c4a6d808f0bf979e07390ceb7e201125fd/pyproject.toml#L22-L23) as well.
