Legacy timezones should be mapped to current valid list

[JordanMagnuson]

This library currently returns a number of timezones that have been deprecated by the tz database (and consequently current versions of programming languages like PHP).

A few legacy timezones that I have noticed being returned recently include:

• America/Buenos_Aires => Should be America/Argentina/Buenos_Aires
• America/Indianapolis => Should be America/Indiana/Indianapolis
• Asia/Calcutta => Should be Asia/Kolkata
• America/Montreal => Doesn't exist in PHP's current list. Should be America/Toronto I believe.
• Etc/GMT-8 => Should be mapped to Asia/Hong_Kong or similar.
• Etc/GMT-2 => Should be mapped to Europe/Amsterdam or similar.

See PHP's deprecated timezone list here: https://www.php.net/manual/en/timezones.others.php
(Which matches up with the tz database. see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)

Ideally all of these legacy timezones should be mapped to currently supported values as listed at e.g. https://www.php.net/manual/en/timezones

[ankit-gaur]

Asia/Calcutta => Should be Asia/Kolkata --> Asia/Calcutta is correct as Asia/Kolkata is deprecated timezone

[JordanMagnuson]

@ankit-gaur actually, it's the opposite. Asia/Calcutta was changed to Asia/Kolkata. Asia/Calcutta is deprecated. See deprecated list at https://www.php.net/manual/en/timezones.others.php or https://en.wikipedia.org/wiki/List_of_tz_database_time_zones