This pull request focuses on improving the Python packaging and release workflow for the project. The most significant changes include enhancing the metadata and configuration for packaging, simplifying the setup script, and updating workflow automation for publishing. These updates make the project easier to distribute and maintain.

Packaging and metadata improvements:

• Expanded and completed metadata in setup.cfg, including package information, dependencies, extras, and package data for proper distribution.

Build and release automation:

• Updated .github/workflows/tests.yml to specify the packages_dir for PyPI uploads, ensuring correct package publishing.

Setup script simplification:

• Simplified setup.py to a single call to setup(), moving all configuration to setup.cfg for cleaner and more maintainable packaging.

Version and changelog updates:

• Bumped the package version to 0.4.3 in sphinx_togglebutton/__init__.py.
• Added changelog entries for recent fixes and improvements in CHANGELOG.md.