v1.2.6

Summary:
This release refactors some of the computations to take advantage of numpy functions (such as einsum, hypot and radians) and to use complex forms of the spherical harmonics. This simplified some of the calculations (such as the clenshaw summations). The documentation also has been updated and new CI tests have been added.

Itemized Changes:

• ci: use new pixi coverage task (#171)
• chore: simplify build to use matplotlib-base (#171)
• chore: bump versions of setuptools and pixi (#172)
• refactor: use np.einsum for spherical harmonic summations (#174)
• refactor: use np.radians to convert from degrees to radians (#174)
• refactor: use np.hypot to calculate the sum of two squares (#174)
• feat: add dunder (magic) methods for mathematical operations (#174)
• test: add fourier vs integration test (#174)
• docs: update documentation to add more sections (#174)
• docs: convert README to markdown (#174)
• feat: add ability to change cache dir (#174)
• docs: make NASA Earthdata an executed notebook (#174)
• refactor: make new map pixi environment (#174)
• test: add failsafe for downloading GRACE files (#174)
• docs: add release notes (including prior) (#174)
• docs: clean up NASA Earthdata notebook
• refactor: simplify clenshaw summations (#175)
• refactor: ruff format (#175)
• ci: add ruff format checker (#175)
• feat: add function to create HTML representations of custom classes (#178)
• fix: case where there are months but it is an integer (#178)
• feat: add ability to use a custom weighting function (#180)
• feat: add functions to convert times to numpy.datetime64 (#183)

Full Changelog: 1.2.5...1.2.6