Add support for M1 Macs (missing darwin/arm build config)

[the80srobot]

The Heroku CLI currently fails to install on M1 Macs, because the requisite tarball doesn't exist.

install.sh can figure out that it needs to set OS to "darwin" and ARCH to "arm", but fails because that tarball doesn't exist on cli-assets.heroku.com.

• [EXISTS] https://cli-assets.heroku.com/heroku-darwin-x64.tar.xz
• [DOES NOT EXIST] https://cli-assets.heroku.com/heroku-darwin-arm.tar.xz
• [EXISTS] https://cli-assets.heroku.com/heroku-linux-x64.tar.xz
• [EXISTS] https://cli-assets.heroku.com/heroku-linux-arm.tar.xz

Can you please update your build config to produce a darwin/arm build?

[the80srobot]

This is related to issue https://github.com/heroku/cli/issues/1731 - I also commented there. The install.sh script might nee updating as well, but the core issue is that you're not producing arm builds for Mac.

[lukasmalkmus]

I just struggled with this as well (two years into ARM Macs and the homebrew formula is still broken for M1/M2 Macs? Come on...). Anyways, the tarball is now there but with the arch being arm64 instead of arm. I managed to install it by putting another elif statement in the script that checks for arm64 and sets the $ARCH=arm64 accordingly. That downloads and installs the correct tarball.