message: [api] Fix download api
  The list examples api was updated in but we also need to update the download example api.
diff: @@ -46,7 +46,7 @@ export default withApiHandler(async function(req: NowRequest, res: NowResponse)
  const example = segment.slice(0, -ext.length);
  await extract('https://github.com/vercel/vercel/archive/master.zip', TMP_DIR);
  - const directory = `${TMP_DIR}/now-master/examples/${example}`;
  + const directory = `${TMP_DIR}/vercel-master/examples/${example}`;
  if (!isDirectory(directory)) {
  return notFound(res, `Example '${example}' was not found.`);
  