Add to indexation

Author: lenvanessen

src/services/Indexes.php

@@ -478,6 +478,10 @@ public function buildMapping(): array
             $mapping[$fieldPrefix . 'attribute_' . $attribute] = $config;
         }
 
+        if(isset($element->postDate) && $element->postDate instanceof \DateTime) {
+            $keywords['attribute_postDate'] = $element->postDate->format(\DateTime::ATOM);
+        }
+
         /**
          * @var ElementInterface $elementType
          */