Add support for protected Attribute accessors (#1339)

* Add support for protected Attribute accessors

* Fix formatting

* Prevent accessors methods marked as private from being added

* Exclude specific accessors based on trait instead of class

* Add changelog entry

* Add clarifying comment

* Fix accessor attributes not working on PHP < 8.1

* Reintroduce method variable to reduce PR clutter

* Change variable name to reduce PR clutter

* Update CHANGELOG.md

---------

Co-authored-by: Barry vd. Heuvel <[email protected]>
Co-authored-by: Barry vd. Heuvel <[email protected]>

tests/Console/ModelsCommand/Attributes/__snapshots__/Test__test__1.php

@@ -20,7 +20,7 @@ use Illuminate\Database\Eloquent\Model;
  */
 class Simple extends Model
 {
-    public function name(): Attribute
+    protected function name(): Attribute
     {
         return new Attribute(
             function (?string $name): ?string {
@@ -40,7 +40,7 @@ class Simple extends Model
      *
      * @return \Illuminate\Database\Eloquent\Casts\Attribute
      */
-    public function notAnAttribute()
+    protected function notAnAttribute()
     {
         return new Attribute(
             function (?string $value): ?string {