[20091] Add macOS Github CI (backport #4100)

[mergify]

This is an automatic backport of pull request #4100 done by Mergify.
Cherry-pick of 8cff0ca has failed:

On branch mergify/bp/2.11.x/pr-4100
Your branch is up to date with 'origin/2.11.x'.

You are currently cherry-picking commit 8cff0ca30.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   .github/workflows/config/default_ci.meta
	modified:   .github/workflows/config/nightly.meta
	new file:   .github/workflows/mac-ci.yml
	new file:   .github/workflows/nightly-mac-ci.yml
	new file:   .github/workflows/reusable-mac-ci.yml
	modified:   .github/workflows/reusable-windows-ci.yml
	modified:   test/blackbox/CMakeLists.txt
	modified:   thirdparty/boost/include/boost/mpl/aux_/integral_wrapper.hpp

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   .github/workflows/windows-ci.yml

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[JesusPoderoso]

2.11.x is EOL, so this backport does not apply.
Closing this PR.