Issue #2913957 by geertvd, mpdonadio: Fix invalid casing in date argument's namespace

core/modules/datetime/src/Plugin/views/argument/Date.php

 <?php
 
-namespace Drupal\datetime\Plugin\views\Argument;
+namespace Drupal\datetime\Plugin\views\argument;
 
 use Drupal\views\Plugin\views\argument\Date as NumericDate;