Use poetry for installation

[wwzeng1]

This PR was copied from sweepai-dev#5 and generated by Sweep.
Resolves #34.
Testing:

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Description

This PR addresses issue #34 by introducing Poetry as a new installation method for the project. It includes the following changes:

• Creation of pyproject.toml file at the root of the repository, which is the standard file used by Poetry for dependency management.
• Transfer of dependencies from gpt_migrate/requirements.txt to the pyproject.toml file under the [tool.poetry.dependencies] section.
• Update of the README.md file to include instructions on how to install the project using Poetry, while preserving the existing installation instructions for users who prefer the old method.

Summary of Changes

• Created pyproject.toml file with necessary configurations and dependencies.
• Added new section in README.md titled "Installation using Poetry" with instructions on how to install Poetry and use it to install project dependencies.
• Preserved existing installation instructions in README.md for users who prefer the old method.

Please review and merge this PR. Thank you!

Fixes #34.

To checkout this PR branch, run the following command in your terminal:

git checkout sweep/use-poetry-for-installation