local-website doesn't build with Cordova CLI 9.0+

# Bug Report
Error installing the cordova-labs-local-webserver plugin using Cordova CLI 9+
## Problem
In Cordova 9, there is a change: Deprecate requireCordovaModule for non-Cordova modules.
https://github.com/apache/cordova-lib/pull/707
Both scripts for local-webserver use requireCordovaModule to use `elementtree`, which fails/

### What is expected to happen?
Add the package without errors.

### What does actually happen?
Throws an error

## Information
Create a new Cordova app and add the plugin.
You can use `cordova plugin add cordova-labs-local-webserver`

### Command or Code
cordova plugin add cordova-labs-local-webserver

### Environment, Platform, Device
I've reproduced it using Cordova-lib@12.0.1 with an app using the Cordova platform iOS 7.1.1

### Version information
Cordova-lib@12.0.1 with an app using the Cordova platform iOS 7.1.1

## Checklist

- [x] I searched for existing GitHub issues
- [x] I updated all Cordova tooling to most recent version
- [x] I included all the necessary information above