Trying to get a cron job set up in Vercel. I followed their example, here is my code

module.exports = async function handler(request, response) {
  const authHeader = request.headers.get("authorization");
  if (authHeader !== `Bearer ${process.env.CRON_SECRET}`) {
    return response.json(
      { success: false },
      {
        status: 401,
      }
    );
  }

  try {
    await checkForImageUpdates();
    response.status(200).json({ message: `Updated assets` });
  } catch (e) {
    console.error("Error updating assets", error);
    response.status(500).json({ error: "Error updating assets" });
  }
};

When running, the logs are erroring with TypeError: request.headers.get is not a function at handler. It was my understanding that they send in the CRON_SECRET env var if supplies (which I did add it in my env vars). Any dieas what I'm doing wrong?