pack buildpack new --targets creates buildpack.toml with wrong field/table names for distro name/version

[edmorley]

Summary

The pack buildpack new command has a --targets option that allows for pre-populating the [[targets]] table in the generated buildpack.toml file.

However, the command currently uses the wrong field and table names if a distro name/version is specified:

• targets.distributions (instead of targets.distros)
• versions of type array (instead of version of type string)

xref:

• Buildpack API inconsistency around naming/data-type of targets.distros.version field in buildpack.toml  spec#401
• Update RFC 0096 (stacks removal) to match what landed in the spec rfcs#310

cc @natalieparellano

---

Reproduction

Steps

1. pack buildpack new testcase-targets-distros --api 0.10 --targets "linux/amd64:ubuntu@123"
2. cat testcase-targets-distros/buildpack.toml

Current behavior

# ...
[[targets]]
  os = "linux"
  arch = "amd64"

  [[targets.distributions]]
    name = "ubuntu"
    versions = ["123"]

Expected behavior

# ...
[[targets]]
  os = "linux"
  arch = "amd64"

  [[targets.distros]]
    name = "ubuntu"
    version = "123"

---

Environment

$ pack --version
0.33.2+git-f2cffc4.build-5562

[natalieparellano]

Thanks @edmorley - this should be simple enough to fix. I put up #2123 for now