Cell row should be an int

src/PhpSpreadsheet/Cell/Coordinate.php

@@ -30,7 +30,7 @@ abstract class Coordinate
     public static function coordinateFromString($cellAddress)
     {
         if (preg_match('/^([$]?[A-Z]{1,3})([$]?\\d{1,7})$/', $cellAddress, $matches)) {
-            return [$matches[1], $matches[2]];
+            return [$matches[1], (int) $matches[2]];
         } elseif (self::coordinateIsRange($cellAddress)) {
             throw new Exception('Cell coordinate string can not be a range of cells');
         } elseif ($cellAddress == '') {