[fix] defaultRootIndex is not working - also not a valid option

[mikevalstar]

Describe the bug

Node.js version: 16.13.1

OS version: MacOS 12.6

Description: When setting the defaultRootIndex it does not work; specifically setting it to 'index.ts'

Actual behavior

The option on start does not seem to be taken into account. Additionally this variable is not part of the types on the object.

Expected behavior

it should use this option

Code to reproduce

const bree = new Bree({
  root: path.join(__dirname, 'jobsv2'),
  defaultRootIndex: 'index.ts',
  defaultExtension: 'ts',
  acceptedExtensions: ['ts', 'js', 'mjs'],
  outputWorkerMetadata: true,
});

Checklist

• I have searched through GitHub issues for similar issues.
• I have completely read through the README and documentation.
• I have tested my code with the latest version of Node.js and this package and confirmed it is still not working.