remove deprecated strftime in 4.1 branch

Author: pxpm

src/resources/views/crud/fields/datetime.blade.php

@@ -9,7 +9,7 @@
 
 $timestamp = strtotime(old(square_brackets_to_dots($field['name'])) ? old(square_brackets_to_dots($field['name'])) : (isset($field['value']) ? $field['value'] : (isset($field['default']) ? $field['default'] : '' )));
 
-$value = $timestamp ? strftime('%Y-%m-%dT%H:%M:%S', $timestamp) : '';
+$value = $timestamp ? date('Y-m-d\TH:i:s', $timestamp) : '';
 @endphp
 
 @include('crud::fields.inc.wrapper_start')