message: feat: Add v1 field getter
diff: @@ -32,6 +32,12 @@ pub struct CrateListingV1 {
  v1: BTreeMap<PackageId, BTreeSet<String>>,
  }
  +impl CrateListingV1 {
  + pub fn v1(&self) -> &BTreeMap<PackageId, BTreeSet<String>> {
  + &self.v1
  + }
  +}
  +
  pub fn resolve_root(flag: Option<&str>, config: &Config) -> CargoResult<Filesystem> {
  let config_root = config.get_path("install.root")?;
  Ok(flag
  