Add MacOS packaging (brew)

[dhiltgen]

This should make it easier for folks to install the CLI on MacOS.

A few notes:

• I'm not happy with the fact that versions have to be pinned, and there doesn't seem to be a way to make the version driven by livecheck and semver calculations. (something to keep exploring...)
• The notes in the README are untested, so they may require some refinement once this is merged. I tested it locally and it seemed to work.

[codecov-io]

Codecov Report

Merging #86 (44201ab) into main (7cb7096) will increase coverage by 6.97%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main      #86      +/-   ##
==========================================
+ Coverage   52.73%   59.70%   +6.97%     
==========================================
  Files          39       39              
  Lines        2611     2611              
==========================================
+ Hits         1377     1559     +182     
+ Misses       1049      858     -191     
- Partials      185      194       +9     

Flag	Coverage Δ
integration-tests	59.24% <ø> (+6.99%)	⬆️
unit-tests	4.21% <ø> (ø)

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Impacted Files	Coverage Δ
pkg/driver/kubernetes/factory.go	70.54% <0.00%> (+2.73%)	⬆️
pkg/build/build.go	44.11% <0.00%> (+9.00%)	⬆️
pkg/driver/kubernetes/driver.go	72.72% <0.00%> (+10.98%)	⬆️
pkg/driver/kubernetes/manifest/manifest.go	96.83% <0.00%> (+39.52%)	⬆️

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