// revision is the commit hash for the specified revision.
  // +optional
  optional string revision = 2;

  // directory is the target directory name.
  // Must not contain or start with '..'.  If '.' is supplied, the volume directory will be the
  // git repository.  Otherwise, if specified, the volume will contain the git repository in
  // the subdirectory with the given name.
  // +optional
  optional string directory = 3;