Backports Entry Points Selectable

backports.entry_points_selectable is a compatibility shim that provides selectable entry points, specifically designed to ease the adoption of `importlib.metadata` 3.6+. It enables 'selectable' entry points (passing keyword arguments to `entry_points()` or invoking `.select()` on the result) even on older Python versions (prior to 3.10) or when `importlib_metadata` is older than 3.6. The current version is 1.3.0, and it receives updates as needed to maintain compatibility.