v1.9.1

What's Changed

• Update grok-4.20 and multi-agent model variants in ChatModel by @shawnthapa in https://github.com/xai-org/xai-sdk-python/pull/117
• Bump version from 1.9.0 to 1.9.1 by @shawnthapa in https://github.com/xai-org/xai-sdk-python/pull/118

Full Changelog: https://github.com/xai-org/xai-sdk-python/compare/v1.9.0...v1.9.1