chore: upgrade to Symfony 6.4

src/Form/DataTransformer/EntityToIdentifierTransformer.php

@@ -22,7 +22,7 @@ class EntityToIdentifierTransformer implements DataTransformerInterface
         $this->identifier = $identifier;
     }
 
-    public function transform($value)
+    public function transform($value): mixed
     {
         if (null === $value) {
             return null;
@@ -33,7 +33,7 @@ class EntityToIdentifierTransformer implements DataTransformerInterface
         return call_user_func([$value, $getter]);
     }
 
-    public function reverseTransform($value)
+    public function reverseTransform($value): mixed
     {
         if (empty($value)) {
             return null;

src/Form/DataTransformer/FeedbackToRatingsTransformer.php

@@ -11,13 +11,13 @@ class FeedbackToRatingsTransformer implements DataTransformerInterface
     {
     }
 
-    public function transform(mixed $value)
+    public function transform(mixed $value): mixed
     {
         // Not in use
         return $value;
     }
 
-    public function reverseTransform(mixed $value)
+    public function reverseTransform(mixed $value): mixed
     {
         $feedbackRatings = [];
 

src/Form/DataTransformer/FirstDayOfMonthDateTransformer.php

@@ -6,12 +6,12 @@ use Symfony\Component\Form\DataTransformerInterface;
 
 class FirstDayOfMonthDateTransformer implements DataTransformerInterface
 {
-    public function transform($value)
+    public function transform($value): mixed
     {
         return $value;
     }
 
-    public function reverseTransform($value)
+    public function reverseTransform($value): mixed
     {
         if (!is_array($value)) {
             return $value;