chore!: remove Kirby 3 support

Author: johannschopplich

README.md

@@ -39,7 +39,6 @@ Detailed instructions on how to use these features can be found in the [usage](#
 
 ## Requirements
 
-- Kirby 3 or
 - Kirby 4
 
 Kirby is not a free software. You can try it for free on your local machine but in order to run Kirby on a public server you must purchase a [valid license](https://getkirby.com/buy).

index.php

@@ -8,11 +8,6 @@
     'JohannSchopplich\\Headless\\Api\\Middlewares' => 'src/classes/Api/Middlewares.php'
 ], __DIR__);
 
-// Add backwards compatibility for Kirby 3
-if (!class_exists(\Kirby\Content\Field::class)) {
-    class_alias(\Kirby\Cms\Field::class, \Kirby\Content\Field::class);
-}
-
 App::plugin('johannschopplich/headless', [
     'hooks' => [
         // Explicitly register catch-all routes only when Kirby and all plugins