feat(response): Add merge violations helper method (#1114)

Author: klausi

src/GraphQL/Response/Response.php

@@ -40,4 +40,11 @@ public function getViolations(): array {
     return $this->violations;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function mergeViolations(ResponseInterface $source): void {
+    $this->violations = array_merge($this->violations, $source->getViolations());
+  }
+
 }

src/GraphQL/Response/ResponseInterface.php

@@ -37,4 +37,9 @@ public function addViolations(array $messages, array $properties = []): void;
    */
   public function getViolations(): array;
 
+  /**
+   * Adds the violations from another response to this response.
+   */
+  public function mergeViolations(ResponseInterface $source): void;
+
 }