feat: implement automatic contributor recognition in CHANGELOG for releases

[Copilot]

This PR implements automatic contributor recognition in the CHANGELOG.md file for each release, addressing the community request to thank contributors similar to the AWS MCP server approach.

What's Changed

🚀 Automatic Contributor Recognition

• New GitHub Action workflow automatically triggers when releases are published
• Extracts contributors from git commits and co-author tags between releases
• Updates CHANGELOG.md with formatted contributor list and release information
• Supports multiple trigger types: GitHub releases, manual dispatch, and repository_dispatch for Azure DevOps integration

📝 Manual Changelog Generation

• git-cliff integration with conventional commit parsing for organized changelog generation
• GitHub API integration to pull contributor information and first-time contributor detection
• Automatic categorization of changes (Features, Bug Fixes, Documentation, etc.)
• Creates Pull Request with generated changelog for review

⚙️ Configuration & Documentation

• Root-level CHANGELOG.md that links to existing server-specific changelogs
• git-cliff configuration (cliff.toml) tailored for the Microsoft MCP repository
• Comprehensive documentation explaining the system and how to use it
• Updated README with contributor recognition section

Integration Benefits

This seamlessly integrates with the existing Azure DevOps release pipeline without requiring any changes. When the pipeline calls gh release create, the GitHub webhook automatically triggers the contributor update workflow.

The implementation also addresses the merge conflict problem mentioned in the issue comments by automating changelog generation, eliminating the need for manual CHANGELOG.md editing.

Example Output

When a release is published, the CHANGELOG.md will be automatically updated with:

## [1.2.0] - 2024-01-15

### Contributors 👥

Thanks to all the contributors who made this release possible:

- [@username1](https://github.com/username1) - *first-time contributor* 🎉
- [@username2](https://github.com/username2)
- John Doe

Conventional Commits Support

The system supports conventional commit prefixes for automatic categorization:

• feat: → 🚀 Features
• fix: → 🐛 Bug Fixes
• docs: → 📚 Documentation
• perf: → ⚡ Performance
• And more...

Fixes #156.

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