feat!: return types to the code generator interface

src/QUI/ERP/Coupons/CodeGeneratorInterface.php

@@ -15,5 +15,5 @@ interface CodeGeneratorInterface
      * @param string $prefix (optional)
      * @return string
      */
-    public static function generate($prefix = '');
+    public static function generate(string $prefix = ''): string;
 }

src/QUI/ERP/Coupons/CodeGenerators/SimpleString.php

@@ -30,7 +30,7 @@ class SimpleString implements CodeGeneratorInterface
      * @return string
      * @throws Exception
      */
-    public static function generate($prefix = ''): string
+    public static function generate(string $prefix = ''): string
     {
         $characters = array_merge(
             range('A', 'Z'),

src/QUI/ERP/Coupons/CodeGenerators/Uuid.php

@@ -13,7 +13,7 @@ class Uuid implements CodeGeneratorInterface
      * @param string $prefix (optional)
      * @return string
      */
-    public static function generate($prefix = ''): string
+    public static function generate(string $prefix = ''): string
     {
         return $prefix . UuidCreator::uuid1()->toString();
     }