[8.x] Clear config after dumping auto-loaded files

[driesvints]

I can't remember the amount of times I debugged issues where people were seeing problems with their app due to them not clearing their config cache after installing new packages. Usually caching config files locally isn't very useful yet it still happens a lot. By clearing config cache after installing new packages we can prevent them from running into these issues.

Also added composer/composer as a dev dependency since it's used in the ComposerScripts class.

[GrahamCampbell]

Also added composer/composer as a dev dependency since it's used in the ComposerScripts class.

Is it? Are you sure we don't just need their plugin API?

[driesvints]

@GrahamCampbell

framework/src/Illuminate/Foundation/ComposerScripts.php

Line 5 in 5dffaf6

use Composer\Script\Event;