Fixed PHP 8.1: strftime and gmstrftime functions are deprecated

[raortegar]

According to the PHP 8.1 documentation the use of strftime fucntion is deprecated. See this link for more information:
https://php.watch/versions/8.1/strftime-gmstrftime-deprecated
https://www.php.net/manual/en/function.strftime.php

[jtojnar]

Thanks. Unfortunately, the date function accepts a different format, even the default value of the $date_format argument is not supported (compare the tables for DateTime::format and strftime).

I would suggest deprecating get_local_date method and adding get_date_raw(): ?string and get_datetime(): ?DateTime methods, corresponding to the first and second if branches, respectively. The local formatting would then be a responsibility of the consumer.