ElasticSearch v8 support (#1662)

* ElasticSearch v8 support
* CI updates

Co-authored-by: Thomas Müller <mimmi20@live.de>

tests/Monolog/Handler/SymfonyMailerHandlerTest.php

@@ -30,6 +30,13 @@ class SymfonyMailerHandlerTest extends TestCase
             ->getMock();
     }
 
+    public function tearDown(): void
+    {
+        parent::tearDown();
+
+        unset($this->mailer);
+    }
+
     public function testMessageCreationIsLazyWhenUsingCallback()
     {
         $this->mailer->expects($this->never())