Reduces extra memory usage on `__destruct()` calls (#3094)

* fix: Reduces memory usage on __destruct() call

* docs: CHANGELOG.md

Co-authored-by: Jose Rodriguez <jose.rodriguez@zecovery.com>

CHANGELOG.md

@@ -25,7 +25,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 
 ### Fixed
 
-- Nothing
+- Reduces extra memory usage on `__destruct()` calls
 
 
 ## 1.25.2 - 2022-09-25

src/PhpSpreadsheet/Collection/Cells.php

@@ -465,7 +465,7 @@ class Cells
      */
     private function getAllCacheKeys()
     {
-        foreach ($this->getCoordinates() as $coordinate) {
+        foreach ($this->index as $coordinate => $value) {
             yield $this->cachePrefix . $coordinate;
         }
     }