deps(composer): bump mcp/sdk in the composer-dependencies group

Bumps the composer-dependencies group with 1 update: [mcp/sdk](https://github.com/modelcontextprotocol/php-sdk).


Updates `mcp/sdk` from 0.5.0 to 0.6.0
- [Release notes](https://github.com/modelcontextprotocol/php-sdk/releases)
- [Changelog](https://github.com/modelcontextprotocol/php-sdk/blob/main/CHANGELOG.md)
- [Commits](modelcontextprotocol/php-sdk@v0.5.0...v0.6.0)

---
updated-dependencies:
- dependency-name: mcp/sdk
  dependency-version: 0.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: composer-dependencies
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

composer.json

@@ -1,7 +1,7 @@
 {
   "require": {
     "php": "^8.1",
-    "mcp/sdk": "^0.5.0",
+    "mcp/sdk": "^0.6.0",
     "nyholm/psr7": "^1.8",
     "nyholm/psr7-server": "^1.1"
   },