Changes

Explicit package re-exports using __all__ (see: #23)
Renamed __version__.py to __metadata__.py (metadata items still re-exported in base package)
Updated linter from pylint to flake8 with plugins (see: #13)
Updated codebase to pass new linting
Upgraded poetry.lock lockfile dependencies for development (see: #19)
Updated codebase to match latest type-checking and linting versions
Added Github Actions CI for linting, type-checking, unit-testing and coverage (see: #7)
Added README.md badges for the above Github Actions

Closes

Closes (#23): Fix PyLance Private Import Message
Closes (#13): Enhancement: Investigate flake8 and its plugins
Closes (#19): Enhancement: Investigate removal of poetry.lock file from version control
Closes (#7): Enhancement: Add lint, type check and unit test merge checks