Expand Time for interface

[MGatner]

Description
Many libraries use DateTimeInterface to allow DateTime or DateTimeImmutable. In a few cases in Time our functions are already compatible with either yet the docblocks limit it to DateTime. This PR expands the use for the interface, with one deprecation for an explicit method type.

Checklist:

• Securely signed commits
• Component(s) with PHPdocs
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[iRedds]

I suggest changes within this PR.
Replace this code:

CodeIgniter4/system/I18n/Time.php

Lines 1233 to 1248 in 9896c24

	if ($time instanceof Time)
	{
	$time = $time->toDateTime()
	->setTimezone(new DateTimeZone('UTC'));
	}
	elseif ($time instanceof DateTime)
	{
	$time = $time->setTimezone(new DateTimeZone('UTC'));
	}
	elseif (is_string($time))
	{
	$timezone = $timezone ?: $this->timezone;
	$timezone = $timezone instanceof DateTimeZone ? $timezone : new DateTimeZone($timezone);
	$time = new DateTime($time, $timezone);
	$time = $time->setTimezone(new DateTimeZone('UTC'));
	}

On cleaned of duplication.

 if ($time instanceof Time) 
 { 
 	$time = $time->toDateTime(); 
 } 
 elseif (is_string($time)) 
 { 
 	$timezone = $timezone ?: $this->timezone; 
 	$timezone = $timezone instanceof DateTimeZone ? $timezone : new DateTimeZone($timezone); 
 	$time     = new DateTime($time, $timezone); 
  } 

 if ($time instanceof DateTimeInterface) 
 { 
 	$time = $time->setTimezone(new DateTimeZone('UTC')); 
 } 

[MGatner]

I did it like this because DateTimeInterface doesn't actually have a setTimeZone() method. It might be okay to assume it since the interface is internal:

It is not possible to implement this interface with userland classes.

I'm not sure if PHPStan would complain though.

[iRedds]

This is just a suggestion and I'm not really against using your condition.

$time instanceof DateTime || $time instanceof DateTimeImmutable

The main thing is to get rid of duplication.

[MGatner]

Got it! If you can add it as an inline suggestion I can accept it on mobile, otherwise it will need to wait until I'm back on desktop.

[MGatner]

@iRedds I think I got that taken care of.