Bmi-tester

- Nothing changed yet.

- Fix docs build (36)
- Updates for Python 3.12 (35)
- Move static metadata to setup.cfg; update requirements; update CI workflows (32)

- Fixed documentation builds on readthedocs (31)
- Added usage and installation instructions to the README,
and did a general cleaning up of the docs (30)
- Fixed a bug when validating some cf-compliant units (29)
- Added gimli.units as a requirement for unit parsing (29)
- Added GitHub actions for continuous integration (28)

- Removed the test for set_value as it's just too dangerous (26)
- Fixed tests that use get_grid_node_count on grids that
are not unstructured (27)

- Change tests that use ID arrays (e.g. face_nodes, edge_nodes, etc.) to
allocate those array buffers as int32 (25)

- Fixed a bug in the unstructured grid tests (24)