Timezone fixes for php 8.1 (#490)

* Added simple test for TimeZoneHelper #461
* TimeZone offset: don't use float values for columns that could be array keys #461

src/User/Helper/TimezoneHelper.php

@@ -36,7 +36,8 @@ class TimezoneHelper
             $timeZones[] = [
                 'timezone' => $timeZone,
                 'name' => "{$timeZone} (UTC " . ($offset > 0 ? '+' : '') . "{$offset})",
-                'offset' => $offset,
+                // As of PHP 8.1 array keys cannot be float. Offset is used for sorting only
+                'offset' => $offset * 100,
             ];
         }
 

src/User/Validator/TimeZoneValidator.php

@@ -12,6 +12,7 @@
 namespace Da\User\Validator;
 
 use Da\User\Contracts\ValidatorInterface;
+use DateTimeZone;
 
 class TimeZoneValidator implements ValidatorInterface
 {
@@ -24,6 +25,6 @@ class TimeZoneValidator implements ValidatorInterface
 
     public function validate()
     {
-        return in_array($this->timezone, timezone_identifiers_list(), false);
+        return in_array($this->timezone, DateTimeZone::listIdentifiers(), false);
     }
 }