Add test for L2C using optimistic locks

As explained in #7067, fields with `@ORM\Version` annotation were not
being added to L2C cached data.

tests/Doctrine/Tests/ORM/Functional/Ticket/GH7067Test.php

@@ -0,0 +1,69 @@
+<?php
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+final class GH7067Test extends \Doctrine\Tests\OrmFunctionalTestCase
+{
+    public function setUp() : void
+    {
+        $this->enableSecondLevelCache();
+        parent::setUp();
+
+        $this->setUpEntitySchema([GH7067Entity::class]);
+    }
+
+    /**
+     * @group 7067
+     */
+    public function testSLCWithVersion() : void
+    {
+        $entity             = new GH7067Entity();
+        $entity->lastUpdate = new \DateTime();
+
+        $this->_em->persist($entity);
+        $this->_em->flush();
+        $this->_em->clear();
+
+        /** @var GH7067Entity $notCached */
+        $notCached = $this->_em->find(GH7067Entity::class, $entity->id);
+
+        self::assertNotNull($notCached->version, 'Version already cached by persister above, it must be not null');
+
+        $notCached->lastUpdate = new \DateTime();
+
+        $this->_em->flush();
+        $this->_em->clear();
+    }
+}
+
+/**
+ * @Entity()
+ * @Cache(usage="NONSTRICT_READ_WRITE")
+ */
+class GH7067Entity
+{
+    /**
+     * @Id
+     * @GeneratedValue
+     * @Column(type="integer")
+     *
+     * @var int
+     */
+    public $id;
+
+    /**
+     * @Column(type="datetime")
+     *
+     * @var \DateTime
+     */
+    public $lastUpdate;
+
+    /**
+     * @Column(type="datetime")
+     * @Version
+     *
+     * @var \DateTime
+     */
+    public $version;
+}