message: fix version parsing err
diff: @@ -195,6 +195,7 @@ function parseVersionJson(versionString: string): Version {
  if (!nativArt) return empty;
  return new Native(lib.name, lib.downloads.classifiers[classifier], lib.extract ? lib.extract.exclude ? lib.extract.exclude : undefined : undefined);
  } else {
  + if(!lib.downloads) return empty;
  return new Library(lib.name, lib.downloads.artifact)
  }
  }).filter(l => l !== empty)
  