v0.6.0

Migration to pyproject.toml packaging

Added

• pyproject.toml for package and dependency management

Changed

• Updated setup.py to delegate most package management to pyproject.toml; maintains the get_version functionality
• Updated copyright year in headers

Removed

• setup.py and version.py since single-source version moved to pyproject.toml and kspdg/__init__.py. See https://packaging.python.org/en/latest/guides/single-sourcing-package-version/
• requirements.txt since there are no "pinned" or "concrete" dependencies as kspdg is not (yet?) intended to be released as a stand-alone app. For further information about the intended role of requirements.txt, see and setup vs requirements and use of requirements w/ pyproject
• KSPDG Challenge announcement from README

Full Changelog: v0.5.1...v0.6.0