composer.json: remove --prefer-lowest (#1217)
composer.json: remove --prefer-lowest (#1217)

IMHO it's impractical to expect this package to have to work with the
"first release of Laravel for any major release" even when there are
already sever more releases: no one is/should stick to that version.

This is a re-submit of https://github.com/barryvdh/laravel-ide-helper/pull/1076

See also:
- https://github.com/barryvdh/laravel-ide-helper/pull/1216#issuecomment-831029022
- https://github.com/barryvdh/laravel-ide-helper/pull/1185#issuecomment-831029353
barryvdh/laravel-ide-helper