Add special dev to composer keywords

[jnoordsij]

Summary

The special dev keyword will warn users who run composer require barryvdh/laravel-ide-helper with the following prompt:

> composer require barryvdh/laravel-ide-helper
The package you required is recommended to be placed in require-dev (because it is tagged as "dev") but you did not use --dev.
Do you want to re-run the command with --dev? [yes]?

See also https://getcomposer.org/doc/04-schema.md#keywords.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Misc. change (internal, infrastructure, maintenance, etc.)

Checklist

• Existing tests have been adapted and/or new tests have been added
• Update the README.md
• Code style has been fixed via composer fix-style

[mfn]

Had no idea, love it!

[barryvdh]

Yeah nice, did not know this :)