Implement Buildpack RFC 0070: New Buildpack Descriptor Keys

[ryanmoran]

Summary

Buildpack RFC0070 introduces some new fields into the buildpack.toml file. These fields include description, keywords, and licenses. The specific changes to the buildpack.toml would look like the following:

[buildpack]
description = "<buildpack description>"
keywords = [ "<string>" ]

[[buildpack.licenses]]
type = "<string>"
uri = "<uri>"

To support this, we will need to make changes to both jam and the top-level packit API.

Proposal

1. When we jam pack a buildpack that includes these new keys, and is specifying buildpack API >= 0.6, include these keys in the built buildpack artifact.

2. Include these fields in the packit.BuildpackInfo type so that they can be accessed by the buildpack itself at runtime should they need to.

[sophiewigmore]

Waiting on changes to jam before this can be closed out.

[ryanmoran]

I just opened paketo-buildpacks/jam#23 on the jam repo. Can we consider this closed and deal with jam in its own repo?

[sophiewigmore]

yes! thanks @ryanmoran