Removed PHP 7 dependencies

Author: Matt Janssen

src/Model/ApiResponseResponseModel.php

@@ -42,7 +42,7 @@ public function jsonSerialize(): array
     /**
      * {@inheritdoc}
      */
-    public function arraySerialize(array $group = []): array
+    public function arraySerialize(array $group = [])
     {
         return $this->jsonSerialize();
     }

src/Serializer/Adapter/ArraySerializerAdapter.php

@@ -18,7 +18,7 @@ class ArraySerializerAdapter implements SerializerAdapterInterface
     /**
      * {@inheritdoc}
      */
-    public function serialize($data, array $groups = []): string
+    public function serialize($data, array $groups = [])
     {
         $jsonString = json_encode($this->serializedMixed($data, $groups));
 

src/Serializer/ArraySerializable.php

@@ -15,5 +15,5 @@ interface ArraySerializable
      * @param array $group
      * @return string[]
      */
-    public function arraySerialize(array $group = []): array;
+    public function arraySerialize(array $group = []);
 }