Modernise build tooling and configuration

[MarkBird]

Transition the project from the old-school setup.py style to the more modern pyproject.toml approach.

[dabapps-robot]

Nice PR — this is a solid modernization and a clear improvement overall. Moving to pyproject.toml, using python -m build, and switching to trusted publishing via pypa/gh-action-pypi-publish all look like the right direction.

A couple of things worth double-checking before merge:

1. simple_robots.__version__ was removed

   • Previously this was part of the package surface in __init__.py.
   • If any consumers (or your own docs/tests) reference simple_robots.__version__, this is a breaking change.
   • Might be worth keeping a compatibility __version__ export (or explicitly calling out its removal in release notes).

2. Python support floor is now >=3.10

   • This is fine if intentional, but it is a meaningful support-policy change versus the previous workflow using 3.8.
   • Worth confirming docs/classifiers/changelog are aligned so users aren’t surprised.

If those two points are intentional and documented, this looks ready to merge from my side.