gaussdb-django 4.2.1: License Compliance, Documentation Improvements & Minor Release

[pangpang20]

Description

This is a minor maintenance and compliance release for gaussdb-django.
The primary goals are:

• Explicitly add proper BSD-3-Clause attribution and copyright notices for code derived from the Django project (required for license compliance).
• Improve project metadata, documentation, and tooling compatibility.
• Prepare and publish version 4.2.1 on PyPI.

No new features or behavioral changes to the database backend are introduced.

Changes Made

• Added full BSD-3-Clause attribution block for Django-derived code to the top-level LICENSE file
• Added clear license/copyright headers to every module under gaussdb_django/ that contains code derived from Django
• Updated README.md:
  • Added PyPI status badges (package version + supported Python versions)
  • Fixed the official GaussDB product link
  • Simplified and clarified the license section
• Reverted license field in pyproject.toml from object to simple string ("BSD-3-Clause") for maximum tool compatibility
• Modernized pyproject.toml structure and added license-files = ["LICENSE"]
• Bumped project version from 4.2.0 → 4.2.1 in pyproject.toml
• Merged latest changes from the 4.2.0 branch (housekeeping)

Testing

• All existing unit tests continue to pass locally with Django 4.2.x and GaussDB
• Verified that the package builds correctly with build/pep517 and installs via pip
• Confirmed that the generated wheel on PyPI contains the updated LICENSE file and correct metadata
• Manual smoke test of a simple Django project using gaussdb-django==4.2.1 succeeded (model creation, migrations, basic CRUD)

Additional Notes

• This release is fully license-compliant with Django’s BSD-3-Clause terms.
• No runtime behavior of the GaussDB backend has changed.
• Users upgrading from 4.2.0 can safely upgrade; no migration or settings changes are required.
• The package is now available on PyPI as gaussdb-django==4.2.1.