Bump @modelcontextprotocol/sdk from 1.18.0 to 1.20.0

Bumps [@modelcontextprotocol/sdk](https://github.com/modelcontextprotocol/typescript-sdk) from 1.18.0 to 1.20.0.
- [Release notes](https://github.com/modelcontextprotocol/typescript-sdk/releases)
- [Commits](modelcontextprotocol/typescript-sdk@1.18.0...1.20.0)

---
updated-dependencies:
- dependency-name: "@modelcontextprotocol/sdk"
  dependency-version: 1.20.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]