Add support for `composer/installers`

[alexstewartja]

Allows automatic installation into plugins directory via Composer Installer

[boxybird]

@alexstewartja Thanks for the PR!

However, I'm new to the "composer/installers" concept, and after going over their readme, I'm failing to understand how this benefits this package over the current install process.

If you wouldn't mind, I love to understand what problem/issue it solves?

[mortensassi]

@boxybird for me it helps me organizing my wp repos so that others won't miss a critical plugin like this one. with roots/bedrock you have a composer file in the root where i enter all important plugins and having yours marked as "wordpress-plugin" saves the work to manually it to /plugins

[boxybird]

Thanks for helping me understand, @mortensassi.

[alexstewartja]

@boxybird

@mortensassi explained it perfectly. The current install process assumes a plain vanilla WP directory structure. Like @mortensassi, I use Bedrock exclusively for its enhanced application security and pragmatic approach to dependency management.