Fix placeholder compatibility

Author: yajra

src/Html/Editor/Fields/Select2.php

@@ -18,6 +18,15 @@ public function allowClear(bool $state = true): static
         return $this->opts(['allowClear' => $state]);
     }
 
+    /**
+     * @param  string  $value
+     * @return $this
+     */
+    public function placeholder(string $value): static
+    {
+        return $this->optsPlaceholder($value);
+    }
+
     /**
      * @param  string  $text
      * @param  string  $id

tests/FieldTest.php

@@ -196,6 +196,9 @@ public function it_can_create_select2_field()
         $field->processPaginatedResults('username', 'user_id');
         $this->assertStringContainsString('e.text = e.username', $field->opts['ajax']['processResults']);
         $this->assertStringContainsString('e.id = e.user_id', $field->opts['ajax']['processResults']);
+
+        $field->placeholder('New Placeholder');
+        $this->assertEquals('New Placeholder', $field->opts['placeholder']['text']);
     }
 
     /** @test */