async function getPr(prNumber) {
  // https://docs.github.com/en/rest/reference/pulls#get-a-pull-request
  const url = `https://api.github.com/repos/prettier/prettier/pulls/${prNumber}`;
  const response = await fetch(url, {
    Headers: {
      "Content-Type": "application/json",
      Accept: "application/vnd.github.v3+json",
    },
  });
  if (!response.ok) {
    if (response.status === 404) {
      throw new Error(`Pull Request #${prNumber} not found.`);
    }
    throw new Error(response);
  }
  const { title, user } = await response.json();
  return {
    title,
    user: user.login,
  };
}
@param {number} prNumber
@returns {Promise<{ title: string; user: string }>}