cargo ConfigMetadataDependency does not represent all Paketo buildpacks' dependency metadata

[fg-j]

In cargo, there is a ConfigMetadataDependency struct that represents the various metadata that can be found in a [[metadata.dependencies]] entry in a buildpack.toml. This struct includes a Licenses field that is a slice of strings. This matches the structure of buildpack dependency metadata like what shows up in the node-engine buildpack.

However, in buildpacks like the Bellsoft Liberica buildpack, the dependency licenses are represented as an array of TOML objects with type and URI fields.

The result is that cargo cannot decode the buildpack.toml for buildpacks with dependency licenses represented as TOML objects.

This is just one of a few instances where packit makes assumptions about the structure of the metadata in a buildpack.toml. It may be useful to either a) make packit more flexible in how it decodes buildpack.toml, and/or b) spec some requirements for packit-compliant buildpack metadata so that buildpack authors can construct buildpack.toml that work with packit.