pyproject.toml: add homepage and documentation links

[theinhumaneme]

I have added the Homepage and Documentation links as they are not currently available when using the command

pip show guardrailsai

Current Ouput

Name: guardrails-ai
Version: 0.4.5
Summary: Adding guardrails to large language models.
Home-page: 
Author: Guardrails AI
Author-email: contact@guardrailsai.com
License: Apache-2.0
Location: /.../python3.10/site-packages
Requires: coloredlogs, griffe, guardrails-api-client, jwt, langchain-core, lxml, nltk, openai, opentelemetry-exporter-otlp-proto-grpc, opentelemetry-exporter-otlp-proto-http, opentelemetry-sdk, pip, pydantic, pydash, python-dateutil, regex, requests, rich, rstr, tenacity, tiktoken, typer, typing-extensions
Required-by: 

[theinhumaneme]

Thank you :D