Performance: use ImageData when grid has uniform axis spacing

[banesullivan]

Use pv.ImageData over pv.RectilinearGrid when the axes have uniform spacing.

This yields significant performance improvements, especially if wanting to volume render:

import xarray as xr
import pvxarray
import pyvista as pv

ds = xr.tutorial.load_dataset("cells3d")
da = ds.images
nuclei = da.sel(c='nuclei').pyvista.mesh(x="x", y="y", z="z")

pl = pv.Plotter()
pl.add_volume(nuclei, clim=(0, 30000), opacity='sigmoid')
pl.enable_terrain_style()
pl.show()

The tests here are working around an upstream bug: pyvista/pyvista#7686

maintenance

• Updates the GitHub Actions to run again
• Bump the required version of PyVista
• Fix deprecation issues
• More python testing versions

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 67.85714% with 9 lines in your changes missing coverage. Please review.

Project coverage is 44.28%. Comparing base (abd1111) to head (284cb09).

Files with missing lines	Patch %	Lines
pvxarray/io.py	16.66%	5 Missing ⚠️
pvxarray/_version.py	0.00%	2 Missing ⚠️
pvxarray/rectilinear.py	90.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #81      +/-   ##
==========================================
+ Coverage   43.09%   44.28%   +1.18%     
==========================================
  Files          11       11              
  Lines         478      490      +12     
==========================================
+ Hits          206      217      +11     
- Misses        272      273       +1     

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