2.0.0 (Nova v4)

What's changed

• BС: min Nova version is 4.0
• BС: Unlayer class does not expend \Laravel\Nova\Fields\Code class anymore. Instead, it extends abstract basic \Laravel\Nova\Fields\Field class. If you for some reason use options or language methods from Code class (what is non-sense), please remove these usages.

Full Changelog: 1.0.6...2.0.0