Probably don't need `composer/installers` under composer v2?

Nobody has claimed this yet.

Seems like this might be the cause of `composer install` creating a `/Plugin` root folder and installing every package that [has a `type: cakephp-plugin` in their own `composer.json`](https://github.com/loadsys/CakePHP-ConfigReadShell/blob/7a4a69d0f65c3ba70f8eccb0c768becacf32dd6a/composer.json#L4) into that (tracked) folder.

It's not clear to me how to detect whether this plugin is being `composer install`ed via composer v1 or v2, but on the `master / 4.x` branch it's probably safe to [remove `composer/installers` from the `composer.json` file](https://github.com/loadsys/CakePHP-ConfigReadShell/blob/7a4a69d0f65c3ba70f8eccb0c768becacf32dd6a/composer.json#L25) in THIS project.

The issue is fixed when a different project that runs `composer require loadsys/cakephp-config-read:~4.0` should NOT end up with a root `Plugin/` folder when running `composer install`.

Start with composer.json, especially the composer/installers entry around the referenced line, and reproduce installation from another project requiring loadsys/cakephp-config-read:~4.0. Confirm that the dependency is not needed for the master/4.x setup, then verify that composer install no longer creates a root Plugin/ folder or installs cakephp-plugin packages there.

Written by the indexing model from the issue text.