Install homebrew linux runners by default

[erawhctim]

Is this possible?
Ideally brew would be available on the path variable as well.

relevant GH issue
On GH-owned linux runners, we work around this limitation with the following script:

echo "/home/linuxbrew/.linuxbrew/bin:/home/linuxbrew/.linuxbrew/sbin" >>"$GITHUB_PATH"

[edigaryev]

We already have Homebrew in macOS images, and for the Linux, unfortunately, it's not available on arm64:

linux-image-templates/customizations/linux-runner/playbook-runner.yml

Lines 162 to 164 in 39dcd0d

	# Skip installing Homebrew as it's not supported on arm64 Linux yet[1]
	#
	# [1]: https://docs.brew.sh/Homebrew-on-Linux#arm-unsupported

But I think we can install it on amd64, though.

[fkorotkov]

It seems it can run on Arm but needs ruby which we already have. Formulas seems can not support Arm but brew itself seems should work. 🤔

[erawhctim]

got it, thanks! Installing on AMD linux would be helpful right now.

M-series macOS machines are ARM-based, right? brew seems to work on those machines natively; did homebrew add specific support for macOS ARM machines that can't be applied to linux ARM?
(I'm unfamiliar with the specifics around most of this, so bear with me)