Compatibility with 8.2

[remicollet]

Yes, I know... probably too early ;)

========DIFF========
--
       string(26) "1971-02-03 04:05:06.789000"
     }
     string(29) "1971-02-03T04:05:06.789+00:00"
011+ string(56) "O::'ion\\Timestamp'::{date:"1971-02-03 04:05:06.789000"}"
012+ 
013+ Fatal error: Uncaught Error: Invalid serialization data for DateTime object in /dev/shm/BUILD/php82-php-pecl-ion-0.2.1/NTS/tests/serialize/timestamp.php:8
014+ Stack trace:
015+ #0 [internal function]: DateTime->__unserialize(Array)
016+ #1 /dev/shm/BUILD/php82-php-pecl-ion-0.2.1/NTS/tests/serialize/timestamp.php(8): ion\unserialize('O::'ion\\\\Timest...')
017+ #2 {main}
018+   thrown in /dev/shm/BUILD/php82-php-pecl-ion-0.2.1/NTS/tests/serialize/timestamp.php on line 8
011- string(24) "1971-02-03T04:05:06.789Z"
012- object(ion\Timestamp)#%d (3) {
013-   ["precision"]=>
014-   int(247)
015-   ["format"]=>
016-   string(15) "Y-m-d\TH:i:s.vP"
017-   ["date"]=>
018-   string(26) "1971-02-03 04:05:06.789000"
019- }
020- DONE
========DONE========

FAIL ion\serialize/timestamp [tests/serialize/timestamp.phpt] 
========DIFF========
--
     }
     string(22) "2000-10-20T11:11+01:00"
     object(ion\Timestamp)#%d (3) {
070-   ["precision"]=>
071-   int(55)
072-   ["format"]=>
073-   string(12) "Y-m-d\TH:i:s"
       ["date"]=>
072+   ["timezone_type"]=>
073+   int(2)
074+   ["timezone"]=>
075+   string(1) "Z"
     }
     DONE
========DONE========
FAIL ion\Timestamp [tests/Timestamp.phpt]