Motivation and Context

As requested in PR #677, this commit adds a changelog entry for OIDC discovery support.

Key changes include:

• Adding the OIDC discovery feature to the changelog.
• Updating the link in the changelog to point to the latest "OpenID Connect Discovery 1.0 incorporating errata set 2", ensuring developers reference the most up-to-date and accurate specification.

How Has This Been Tested?

N/A

Breaking Changes

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 Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed