Remove PyGEOS support, require Shapely 2+

[jorisvandenbossche]

We don't actually have that much of code complexity from supporting both (at least not compared to pandas, because we mostly dispatch to the geopandas methods), but it does complicate testing a bit (e.g. when tests fail for pygeos), and generally I think shapely 2.0 is widely supported nowadays and already out for more than a year.

[TomAugspurger]

Thoughts on adding shapely>=2 to the dependencies in pyproject.toml? I suppose we get shapely through geopandas, but probably best to state it explicitly so that users don't need an ImportError to discover that their version isn't valid.

[martinfleis]

If there are multiple geometry columns, are they guaranteed to have the same CRS? It seems like there's a CRS on the table but not a GeoSeries.

Yeah, we need that as the min geopandas is 0.12 which does not enforce shapely 2.

[jorisvandenbossche]

Good point to add shapely, done!

[TomAugspurger]

+1. The doc build failure looks related to dask-expr, which is being handled elsewhere.