Add macos build test to modmesh_viewer.yml

[minchuncho]

1. Specify the version of mac os: 12
2. Align the commands with the ones in

   modmesh/.github/workflows/modmesh_pytest.yml

   Line 48 in 9eef4aa

   brew install python3 llvm

[minchuncho]

My old version of CI is as follows:

brew install wget make cmake libccd gcc python3 qt6
pip3 install -U numpy pytest flake8

Curious, I didn't write the following line but the old version still worked.

modmesh/.github/workflows/modmesh_pytest.yml

Line 52 in 9eef4aa

pip3 install -U setuptools

I found that setuptools is a Python package development process library, i.e., enhanced disutils, while disutils is a Python standard library.
May I reach to this conclusion that if setuptools is not installed, then disutils is chosen by default so the old version still ran well?

[yungyuc]

LGTM except the regression to os version alias.

[yungyuc]

Curious, I didn't write the following line but the old version still worked.

modmesh/.github/workflows/modmesh_pytest.yml

Line 52 in 9eef4aa

pip3 install -U setuptools

I found that setuptools is a Python package development process library, i.e., enhanced disutils, while disutils is a Python standard library. May I reach to this conclusion that if setuptools is not installed, then disutils is chosen by default so the old version still ran well?

That is a reasonable guess, I think. I do not know the answer either. It probably does not matter ATM, but could be interesting to learn.

[yungyuc]

Thanks @minchuncho . This addressed #111