v1.8.1

What's Changed

• Update grok-4.20 beta and multi-agent model variants in ChatModel by @shawnthapa in https://github.com/xai-org/xai-sdk-python/pull/107
• Bump version from 1.8.0 to 1.8.1 by @shawnthapa in https://github.com/xai-org/xai-sdk-python/pull/109

Full Changelog: https://github.com/xai-org/xai-sdk-python/compare/v1.8.0...v1.8.1