feat: Include merged PRs and contributors in changelog

[thomas-vilte]

Description

I extended the buildChangelogFromNotes function to include a list of merged pull requests and their authors, as well as a list of all contributors to the release. This provides a more comprehensive and accurate changelog by moving beyond just per-commit references.

Fixes #

Type of Change

• 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 not work as expected)
• Documentation update

How Has This Been Tested?

I added a new unit test, TestBuildChangelogFromNotes_WithMergedPRsAndContributors, to verify that the changelog correctly includes the merged PRs and contributors sections.

• Unit tests
• Integration tests
• Manual test: (describe below)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Test Plan & Evidence

Suggested Manual Verification

• API/Backend: Attach JSON response or logs as evidence of correct behavior
• Performance: Ensure no significant latency increase
• Unit Tests: Run go test ./... and ensure all tests pass
• No Regressions: Verify that related features still work as expected