update(contour_array): add tri_mask kwarg to parameters

[jlarsen-usgs]

• update docstrings for tri_mask kwarg
• re-lint flopy with new version of black (previously 23.3, now 24.1)
• update pyproject.toml, set pytest < 8.0.0

[codecov]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (f8eac0f) 73.0% compared to head (688a10f) 73.0%.

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #2078   +/-   ##
=======================================
  Coverage     73.0%   73.0%           
=======================================
  Files          259     259           
  Lines        59330   59329    -1     
=======================================
  Hits         43332   43332           
+ Misses       15998   15997    -1     

Files	Coverage Δ
flopy/__init__.py	100.0% <ø> (ø)
flopy/export/netcdf.py	49.2% <100.0%> (ø)
flopy/export/shapefile_utils.py	83.7% <ø> (ø)
flopy/mbase.py	69.9% <ø> (ø)
flopy/mf6/data/mfdatastorage.py	71.4% <100.0%> (ø)
flopy/mf6/data/mffileaccess.py	71.3% <100.0%> (ø)
flopy/mf6/mfbase.py	81.8% <ø> (ø)
flopy/mf6/mfpackage.py	69.6% <100.0%> (ø)
flopy/mf6/utils/createpackages.py	6.6% <ø> (ø)
flopy/mf6/utils/model_splitter.py	70.0% <100.0%> (ø)
... and 70 more

... and 1 file with indirect coverage changes

[wpbonelli]

this should no longer be necessary after #2077 but fine for now