chore: point Changelog project URL to CHANGELOG.md

[nicknisi]

The Changelog entry in [project.urls] pointed at the SDK docs page (same as Homepage). This points it at CHANGELOG.md on GitHub so the PyPI sidebar link goes to the actual changelog.

[greptile-apps]

Confidence Score: 5/5

[Low risk] Updates a metadata URL in the package configuration.

The PR appears safe to merge.

Summary

The PR changes the PyPI Changelog project URL from the SDK documentation page to the repository’s CHANGELOG.md.

• The new URL matches the changelog’s path and the repository’s release branch.

_{Reviews (1) · Last reviewed commit: "chore: point Changelog project URL to CH..."}

[ajay-k]

LGTM!