Ability to Specify Build Network for Buildpack Image Builds

[bogdannazarenko]

Existing Skaffold config schema does not allow specifying a container build network for buildpack image builds.

Need to specify build network arrises when trying to build image using buildpack on Google Cloud Build Private Pool and accessing ADC (application default credentials) to further authenticate to Artifact Registry (e.g. private npm registry). ADC are available on docker build network cloudbuild. Google Docs

build:
  - image: myimage
    buildpacks:
         projectDescriptor: project.toml
         network: cloudbuild

The build config should append --network cloudbuild to pack cli