v0.22.0

Added

• Add audience role validation for MCP::Annotations per MCP specification (#422)
• Send SEP-2243 Mcp-Method and Mcp-Name headers per MCP specification (#423)
• Support client-side notifications/cancelled per MCP specification (#425)

Changed

• Conform Tool Schemas to JSON Schema 2020-12 per SEP-2106 (#417)

Fixed

• Fix a SyntaxError on Ruby 2.7.0 caused by arguments forwarding syntax (#419)