[master] Allow Homebrew package manager in all systems but Windows

[cdalvaro]

What does this PR do?

This PR removes the restriction for using mac_brew_pkg module only on macOS systems, since Homebrew can be run in Linux too: https://docs.brew.sh/Homebrew-on-Linux

I think that the module could be renamed to brew_pkg instead of mac_brew_pkg. But I need some help here to understand what changes are needed for this to be made.

Merge requirements satisfied?

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

Commits signed with GPG?

Yes

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[cdalvaro]

ping @dwoz, @s0undt3ch and @krionbsd

[twangboy]

I'm not sure how many people are using homebrew on Linux, but if you want to support Linux, you need to make sure all the homebrew tests run on Linux.

The name of the file doesn't matter that much since the salt loader uses the Virtual Name (__VIRTUAL__). The only place it might be an issue is in tests where the full path to the module is passed as an import.

[cdalvaro]

I'm not sure how many people are using homebrew on Linux, but if you want to support Linux, you need to make sure all the homebrew tests run on Linux.

The name of the file doesn't matter that much since the salt loader uses the Virtual Name (__VIRTUAL__). The only place it might be an issue is in tests where the full path to the module is passed as an import.

OK!

So, since historically Homebrew has been related to macOS, I think it can be OK to leave the package name as mac_brew_pkg.py

[cdalvaro]

I've edited the test tests/pytests/functional/modules/test_mac_brew_pkg.py (ac6aae4) to be run in all platforms except Windows.

However, I'm not sure how to make brew available in those platforms so tests can be run.

[twangboy]

Brew would probably need to be added to the golden images for Linux
That would happen here: https://github.com/saltstack/salt-ci-images
If that's too much work, I'm fine just supporting macOS for now

[cdalvaro]

OK, so I would need to modify at least one Linux base image to install Brew on it.

Should I install Brew in all Linux images, or should I just pick one?

[twangboy]

Just pick one

[cdalvaro]

I have opened saltstack/salt-ci-images#1853 to install brew in Ubuntu x86_64 machines