Add testing for OSX

[charlesbluca]

With our CI matrix significantly slimmed with the switch to DataFusion, now might be a good time to begin doing dedicated tests on OSX, since we are publishing packages for the platform.

[codecov-commenter]

Codecov Report

Merging #859 (6344265) into main (82960ca) will increase coverage by 0.13%. The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #859      +/-   ##
==========================================
+ Coverage   77.44%   77.58%   +0.13%     
==========================================
  Files          71       71              
  Lines        3600     3600              
  Branches      634      634              
==========================================
+ Hits         2788     2793       +5     
+ Misses        685      676       -9     
- Partials      127      131       +4     

Impacted Files	Coverage Δ
dask_sql/_version.py	34.00% <0.00%> (+1.44%)	:arrow_up:

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