docs: update mcp specification document link (#3810)

Fixes #3810

Signed-off-by: Seokjae Lee <seok9211@naver.com>
(cherry picked from commit 788d25e)

Author: doljae

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/mcp/mcp-server-boot-starter-docs.adoc

@@ -383,5 +383,5 @@ You can have multiple beans producing ToolCallbacks. The auto-configuration will
 == Additional Resources
 
 * link:https://docs.spring.io/spring-ai/reference/[Spring AI Documentation]
-* link:https://modelcontextprotocol.github.io/specification/[Model Context Protocol Specification]
+* link:https://modelcontextprotocol.io/specification[Model Context Protocol Specification]
 * link:https://docs.spring.io/spring-boot/docs/current/reference/html/features.html#features.developing-auto-configuration[Spring Boot Auto-configuration]