Merge pull request #35 from designmynight/fix-boost

fix: closes #34 by determining the clause term key instead of using type

src/QueryGrammar.php

@@ -641,9 +641,11 @@ protected function applyBoostOption(array $clause, $value, $where): array
             return $clause[$firstKey]['boost'] = $value;
         }
 
+        $key = key($clause['term']);
+
         $clause['term'] = [
-            'type' => [
-                'value' => $clause['term']['type'],
+            $key => [
+                'value' => $clause['term'][$key],
                 'boost' => $value
             ]
         ];