PHP Generation DateTime::RFC3339 is removed

[tolbon]

Hello team,

I run PHPStorm InspectCode on msgraph-sdk-php
for example src/Beta/Microsoft/Graph/Model/AppCatalog.php line 117

'RFC3339' was removed in 7.2 PHP version

reveal that on 17 files other Model file. PHP Docs says same things.

The fix is replace DateTime::RFC3339 by DateTimeInterface::RFC3339 AB#9200

[SilasKenneth]

Hello @tolbon thanks for taking your time to raise this issue, according to the DateTime documentation, the DateTime implements the DateTimeInterface and the constants in the DateTimeInterface are available in DateTime.

[baywet]

closing since this was resolved with #541