Merge pull request openai#20 from openai/update_doc_reference

Add callout on compatibility w other providers

Author: rm-openai

README.md

@@ -13,6 +13,8 @@ The OpenAI Agents SDK is a lightweight yet powerful framework for building multi
 
 Explore the [examples](examples) directory to see the SDK in action, and read our [documentation](https://openai.github.io/openai-agents-python/) for more details.
 
+Notably, our SDK [is compatible](https://openai.github.io/openai-agents-python/models/) with any model providers that support the OpenAI Chat Completions API format.
+
 ## Get started
 
 1. Set up your Python environment