OpenAI Agent 🤖

Excited to add support for gpt-4-0613 and gpt-3.5-turbo-0613 wrapped around an OpenAI Agent

What's Changed

• Expose prompting to DocumentAgent by @homanp in #100
• OpenAI agent type by @homanp in #102

Full Changelog: v.0.0.17...v.0.0.18