Fix deprecations (#21)

* Resolve deprecations in DoctrineWriter

* Update testFlushAndClear in DoctrineWriterTest

Co-authored-by: Sven Krefeld <sven.krefeld@web.de>

Author: ddeboer

src/DoctrineWriter.php

@@ -193,7 +193,7 @@ public function writeItem(array $item): void
     public function flush()
     {
         $this->objectManager->flush();
-        $this->objectManager->clear($this->objectName);
+        $this->objectManager->clear();
     }
 
     /**

tests/DoctrineWriterTest.php

@@ -291,8 +291,7 @@ public function testFlushAndClear()
         $em = $this->getEntityManager();
 
         $em->expects($this->once())
-            ->method('clear')
-            ->with($this->equalTo(self::TEST_ENTITY));
+            ->method('clear');
 
         $writer = new DoctrineWriter($em, 'Port:TestEntity');
         $writer->finish();