Upgrade shapely to v2.0.1

[Evelyn-M]

Shapely 2.0 is out, which brings many useful functionalities, most importantly the integration of pygeos functionalities (for vectorized operations!). A lot of other packages (such as geopandas etc., may require shapely 2.X in the future, too).
We should check out what other changes this entails, a lot of our operations in climada currently trigger warnings that they will fail under this new version, such as multi-part geometries ceasing to be iterables. A lot of other packages (such as geopandas etc., may require shapely 2.X in the future, too).

We're currently at 1.8, some migration instructions (and updates):
https://shapely.readthedocs.io/en/stable/migration.html

[peanutfun]

We do not restrict the version of shapely ourselves. The packages that require shapely in our dependency tree are geopandas and cartopy. Geopandas >=0.12 supports shapely 2.0, but cartopy does not. We cannot upgrade to shapely 2.0 until a release of cartopy supports it.

[emanuel-schmid]

Looks like cartopy can deal with it now
conda-forge/cartopy-feedstock@61104dd
SciTools/cartopy#2076

[peanutfun]

@Evelyn-M Do you want to give this a try? You will have to remove the version pin on Cartopy and build a new conda environment. This should install cartopy v0.21.1, which is compatible with shapely v2.

[peanutfun]

After #682, we support shapely v2.0. Upgrading makes sense because it provides a significant performance boost.