Hyoga

This small bug-fix release brings hyoga up-to-date with its dependencies following an unintended lapse in development. Support was added for recent versions of Python and [cf_xarray](https://cf-xarray.readthedocs.io), and other minor bugs were fixed, reviving the foundation for upcoming improvements and new features in future releases. Code coverage remains at 67 percent.

This release turns hyoga into more than just a visualization tool. Two functions were added to [open](https://hyoga.readthedocs.io/en/stable/datasets/opening.html) online elevation data ([GEBCO](https://www.gebco.net/)) and monthly climatologies ([CHELSA](https://chelsa-climate.org/)) in custom projections that can be used as [PISM](https://pism.io/) input files for paleoglacier modelling about anywhere on Earth. Minor bugs were fixed. Code coverage decreased to 67 percent.

This release implements profile [interpolation](https://hyoga.readthedocs.io/en/stable/datasets/masking.html) and scale bars, both documented in new [examples](https://hyoga.readthedocs.io/en/stable/examples/index.html#), and fixes a bug in grid interpolation to axes coordinates. Continuous integration has been improved with lazy tests for all plot methods, and monitoring of code coverage, increased from 33 to 73 percent in this release.

This release removes the required dependency on [cartopy](https://scitools.org.uk/cartopy/) by implementing own downloaders for Natural Earth and other (and future) data. All dependencies, and the docs, can be built with pip. Plot methods set aspect ratio to equal, and coordinate labels are hidden by default. Development has moved on a feature-branch squash workflow (as [xarray][https://xarray.dev) and [geopandas](https://geopandas.org)).

This is a major relase implementing several cartographic features. It adds custom colormaps and plot methods for [shaded reliefs](https://hyoga.readthedocs.io/en/stable/datasets/shading.html), and an interface to [open and plot](https://hyoga.readthedocs.io/en/stable/datasets/vectors.html) Natural Earth data and paleoglacier extents. The documentation uses a new theme. A logo and new [examples](https://hyoga.readthedocs.io/en/stable/examples/index.html) were added. The package structure has been reworked to better serve [future plans](https://hyoga.readthedocs.io/en/stable/roadmap.html).

This release includes better masks and a dependency on [cf_xarray](https://cf-xarray.readthedocs.io). Plot methods now search for standard variable `land_ice_area_fraction` for masking and default to using a configurable ice thickness masking point. Masking with `where` remains available and a new [documentation page](https://hyoga.readthedocs.io/en/latest/masking.html) explains masking features.