Addresses deprecation of merge.

doctrine/orm#8461

src/Mapper/AbstractDoctrineMapper.php

@@ -45,10 +45,12 @@ public function save(object $entity): void
  $this->getEntityManager()->flush($entity);
  }
 
+ /**
+ * @deprecated Please use save instead
+ */
  public function update(object $entity): void
  {
- $this->getEntityManager()->merge($entity);
- $this->getEntityManager()->flush();
+ $this->save($entity);
  }
 
  public function delete(object $entity): void