Rtree

- Fix test failure with built library (291 by sebastic)
- Include spatialindex headers and add [get_include()](https://rtree.readthedocs.io/en/latest/misc.html#rtree.finder.get_include) (292 by JDBetteridge)

* Python 3.8+ is now required (273)
* Move project metadata to pyproject.toml (269)
* Refactor built wheels for PyPI (276)
* Fix memory leak when breaking mid-way in `_get_objects` and `_get_ids` (266) (thanks akariv!)

* Fix up type hints 243 (thanks oderby)
* Python 3.11 wheels 250 (thanks ewouth)

* Python 3.7+ is now required (212) (thanks adamjstewart!)
* Type hints (215 and others) (thanks adamjstewart!)
* Python 3.10 wheels, including osx-arm64 224
* Clean up libspatialindex C API mismatches 222 (thanks musicinmybrain!)
* Many doc updates, fixes, and type hints (thanks adamjstewart!) 212 221 217 215
* `__len__` method for index 194
* Prevent get_coordinate_pointers from mutating inputs 205 (thanks sjones94549!)
* linux-aarch64 wheels 183 (thanks odidev!)
* black (218) and flake8 (145) linting

* Fix debug wheels on windows 175

* Wheel upload