Fix GitHub OAuth to send access token via Authorization header

[iceybubble]

GitHub deprecated passing OAuth access tokens via query parameters.
This change updates hello.js to attach the token using the
Authorization: Bearer header for GitHub API requests.

Fixes #713

[iceybubble]

Hello maintainers 👋

I’ve addressed the issue in this pull request and ensured that the changes follow the project’s existing structure and conventions.

I would really appreciate it if you could review the PR when you have time. Please let me know if any changes or improvements are required from my side — I’ll be happy to update it accordingly.

Thank you for your time and for maintaining this project!