docs: async function _main(repository, prNumber) {
    console.log(`Determining target branch for PR ${prNumber} on ${repository}.`);
    const targetBranch = await determineTargetBranch(repository, prNumber);
    console.log(`Target branch is ${targetBranch}.`);
    await exec(`git fetch origin ${targetBranch}`);
    console.log(`Rebasing current branch on ${targetBranch}.`);
    await exec(`git rebase origin/${targetBranch}`);
    console.log('Rebase successful.');
  }