FlagGrouper: Encapsulate instead of subclassing UniqueGrouper (#569)

Fix imports again (#565)

* Fix imports again

* try again

* yet agaoin

Update types (#564)

Fix Grouper import (#560)

* Fix import

* redo CI

* fix name

* fix min deps

* bump min xarray

* importorskip

Add pooch downloader to workaround readthedocs/readthedocs.org#11763 (#…

…547)

no more whats-new (#542)

Speed up geometry encoding (#535)

* Speed up geometry encoding

Closes #534

* cleanup

* just save bool

* optimize dataset creation

* fix typing

Add release.yml

Rewrite unit formatter for pint 0.24 and earlier (#523)

* Rewrite unit formatter for pint 0.24

* add pins in pyproject

* Dimensionless as 1 - skip long test on previous pint

* Skip all dimensionless

Add geometry encoding and decoding functions. (#517)

* Add geometry encoding and decoding functions.

These differ from `shapely_to_cf` and `cf_to_shapely` by returning
all variables. Those function, simply encode and decode geometry-related
variables.

* More geometry functionality

1. Associate geometry vars as coordinates when we can
2. Add `cf.geometries`
3. Geometries in repr
4. Allow indexing by `"geometry"` or any geometry type.