message: [cli] Add `requirePath` to "builds.json" in `vc build`
  Include a `requirePath` property to each "build" in the `builds.json` file which is the absolute path to the Builder entrypoint that was executed.
  This gives context as to which Builder was invoked by `vc build` which helps with introspection / debugging.
diff: @@ -306,6 +306,7 @@ export default async function main(client: Client): Promise<number> {
  const { builder, pkg: builderPkg } = builderWithPkg;
  return {
  require: builderPkg.name,
  + requirePath: builderWithPkg.path,
  apiVersion: builder.version,
  ...build,
  };
  