Support multi-architecture (ARM64) builds

[sophiewigmore]

In order to support multi-architecture builds in the project, we will need to set up buildpacks, builders, and stacks that work on ARM64.

The Procfile is a simple, lightweight first buildpack we could try to enable multi-arch builds for that doesn't require dependencies. As a result, we can use this buildpack to test multi-arch builders down the road.

[dmikusa]

I agree this should be an easy repo and good buildpack for testing.

I don't think there's anything that needs to be done on this repo though. Once we get pipeline-builder updated to generate multi-arch images, and update the pipeline in this repo then it should just start publishing multi-arch.

[jpena-r7]

Agreed and I think this will be useful to figure out the approach for creating multi-arch buildpacks to be replicated elsewhere.

[sophiewigmore]

@dmikusa that's a good point. I'm going to pair up with @anthonydahanne on trying to test out something similar to paketo-buildpacks/syft#204 here, but using the experimental pack CLI binary. just to get the ball rolling. We'll contribute it to pipeline-builder when we have something working

[dmikusa]

That'd be great! If you get something working in that PR, let me know and I can make those changes in pipeline-builder pretty easily. Or if you want to submit a PR, that's great too.

[sophiewigmore]

experimental multi-arch procfile buildpack available at anthonydahanne/procfile:dual-march15