ci: set up github actions for automated build and release

[jrfk]

WHAT

This pull request introduces a new automated workflow for building and publishing the Python package, updates the package version, and makes improvements to the project metadata and build configuration. The main changes are the addition of a GitHub Actions workflow for CI/CD and updates to pyproject.toml to support modern packaging and publishing practices.

Continuous Integration/Continuous Deployment (CI/CD) Workflow:

• Added .github/workflows/workflow.yml to automate building, testing, and publishing the Python package to TestPyPI, PyPI, and GitHub Releases, including artifact signing with Sigstore.
• Introduced .github/workflows/determine_version.py to dynamically determine the package version based on git tags or commit SHA, supporting both release and development builds.

Project Metadata and Build Configuration:

• Updated the package version in pyproject.toml from 0.1.1 to 0.1.2.
• Added [project.urls] section with a repository link to improve discoverability.
• Added [build-system] and [tool.uv.build-backend] sections to specify the build backend and requirements, enabling compatibility with the new workflow and modern Python packaging standards.

WHY

We needed something that could publish automatically.