Add eintrittsdatum to member

src/Data/Member.php

@@ -152,6 +152,7 @@ class Member extends Data
             'staatsangehoerigkeitText' => $this->otherCountry,
             'nameZusatz' => $this->furtherAddress,
             'version' => $this->version,
+            'eintrittsdatum' => $this->joinedAt->format('Y-m-d 00:00:00'),
         ];
     }
 

tests/Unit/Api/PutMemberTest.php

@@ -70,6 +70,7 @@ class PutMemberTest extends TestCase
             'staatsangehoerigkeitText' => 'Land',
             'nameZusatz' => 'Name',
             'version' => 40,
+            'eintrittsdatum' => '2021-02-02 00:00:00',
         ]);
     }