Feat: add exists in migrator (#289)

* Add exists in Migrator

* Fix README

Merge pull request #280 from Magnesium38/handle-parens

Handle Parentheses On Anonymous Settings Migrations

Merge pull request #262 from hamzaelmaghari/patch-2

Update MakeSettingCommand.php

Fix styling

Fix styling

Merge pull request #249 from spatie/revert-241-main

Revert "Use Illuminate\Database\Eloquent\Casts\Json if possible"

Merge pull request #241 from naxvog/main

Use Illuminate\Database\Eloquent\Casts\Json if possible

Merge pull request #235 from spatie/dependabot/github_actions/actions…

…/checkout-4

Bump actions/checkout from 3 to 4

Update docs

Fix styling