feat: gigalixir-24 and heroku-24 support

[gigatim]

Add support for heroku-24 and gigalixir-24 stacks.

[dviramontes]

Any objections to getting this merged?

[FlXlT]

Thank you, @gigatim

Would love to see this PR merged so we can upgrade to Heroku-24. Perhaps @ericmj can give us a hand?

[jc00ke]

Thanks @gigatim! jc00ke@4175ff3

[craiglyons]

@HashNuke With deprecation and upcoming retirement of heroku-20, can this please be merged? I imagine many are hoping for this soon so we can get ahead of issues without having to fork & maintain.

[gigatim]

@HashNuke With deprecation and upcoming retirement of heroku-20, can this please be merged? I imagine many are hoping for this soon so we can get ahead of issues without having to fork & maintain.

We are happy to help anyone move their application over to gigalixir. We have applied these changes and more to our default buildpacks for elixir. Contact help@gigalixir.com if you need assistance moving your application.

[r-guimaraes]

Won't this be merged?

[lairjr]

We need support for heroku-24, can we get this merge?