update dev branches; test shapely dev

[jGaboardi]

This PR:

• updates the mapclassify and spreg branches to main in CI due to failures
• add testing against shapely dev (xref update shapely_dev testing spopt#291)
• resolves seaborn FutureWarning - shade #160

[codecov]

Codecov Report

Merging #161 (bfaa62e) into main (fa5304e) will increase coverage by 0.6%.
The diff coverage is 100.0%.

@@           Coverage Diff           @@
##            main    #161     +/-   ##
=======================================
+ Coverage   75.8%   76.4%   +0.6%     
=======================================
  Files         19      19             
  Lines       1570    1570             
=======================================
+ Hits        1190    1199      +9     
+ Misses       380     371      -9     

Impacted Files	Coverage Δ
splot/_viz_esda_mpl.py	100.0% <100.0%> (ø)
splot/_version.py	40.7% <0.0%> (+2.7%)	⬆️

[martinfleis]

Thanks!