Issue #3454291 by joegraduate: GitLabCI: Fix existing PHPStan issues

Closes #3454291

src/Entity/ConfigSnapshot.php

@@ -164,7 +164,7 @@ class ConfigSnapshot extends ConfigEntityBase implements ConfigSnapshotInterface
     // Sort the items by collection then by name.
     array_multisort($collections, SORT_ASC, $names, SORT_ASC, $this->items);
 
-    parent::save();
+    return parent::save();
   }
 
   /**