Composer Compile step

[phpsa]

buildpacks-php/buildpacks/php/src/package_manager/composer.rs

Line 45 in 53d7f62

// TODO: run `composer compile`? but is that still a good name?

shows that this is a todo still, hovever is documented on the heroku php as usable.

could this step be added back in - understanding that naming is being looked at, but for compatability think it should remain for now.