Fix Xero-mcp-server link in README.md

[harrykeen18]

Linking to unofficial repo causing confusion in readme. Switched with official repo: https://github.com/XeroAPI/xero-mcp-server

Description

Unofficial repo - https://github.com/john-zhang-dev/xero-mcp replaced with official repo - https://github.com/XeroAPI/xero-mcp-server to also match second reference higher up in readme.

Server Details

N/A

Motivation and Context

Could cause confusion and potential serious security issues for unexacting developers who might assume a link from this page must be the official Xero MCP page.

How Has This Been Tested?

Test link works on Readme.

Breaking Changes

No.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

N/A

[olaservo]

Thanks for your contribution to the servers list. This has been merged in this combined PR: #2973