Add ValueCount aggregation

Author: erichard

src/Aggregation/Aggregation.php

@@ -130,4 +130,9 @@ public static function stats(string $name): StatsAggregation
     {
         return new StatsAggregation($name);
     }
+
+    public static function valueCount(string $name, string $field, array $aggregations = []): ValueCountAggregation
+    {
+        return new ValueCountAggregation($name, $field, $aggregations);
+    }
 }

src/Aggregation/ValueCountAggregation.php

@@ -0,0 +1,30 @@
+<?php declare(strict_types=1);
+
+namespace Erichard\ElasticQueryBuilder\Aggregation;
+
+use Erichard\ElasticQueryBuilder\Options\Field;
+use Erichard\ElasticQueryBuilder\Options\SourceScript;
+
+
+class ValueCountAggregation extends MetricAggregation
+{
+    public function __construct(
+        string $nameAndField,
+        Field|SourceScript|string|null $fieldOrSource = null,
+        array $aggregations = []
+    ) {
+        parent::__construct($nameAndField, $fieldOrSource, $aggregations);
+    }
+
+    protected function getType(): string
+    {
+        return 'value_count';
+    }
+
+    protected function buildAggregation(): array
+    {
+        $build = parent::buildAggregation();
+
+        return $build;
+    }
+}