min/max timezone not work

I’m not an English speaker, so please forgive me if there are some improper parts.

The time zone is used at’+9:00′.
When the current time (WP server) time is from 0:00 to 9:00,’Minimum Date’ is not processed correctly.

Example)
timezone ‘+9:00’
Current date: 2021-01-25 Hours 0:00-9:00
‘Minimum Date’ setting: “+5 days”
Date picker UI 2021-01-29 However, after 9:00, it will be 2021-01-30.

In Minimum Date and Maximum Date, the time zone is not processed properly when the format is relative.

https://github.com/carmoreira/date-time-picker-field/blob/master/includes/DateTimePicker.php
public function set_rules()
143行目
$temp_date = strtotime( $opts['max_date'] );

Timezone cannot be processed with strtotime.
I want you to replace it with the one that uses the time zone of DateTime or date_create ().

			/*2021.01 ADD get $tzone*/
			$tzone              = get_option( 'timezone_string' );
			if ( isset( $opts['datepicker'] ) && 1 === intval( $opts['datepicker'] ) ) {
				$format       .= $opts['dateformat'];
				$clean_format .= $this->format( $opts['dateformat'] );

				// max date.
				if ( isset( $opts['max_date'] ) && $opts['max_date'] !== '' ) {
					/*2021.01 Edit set $tzone
					$temp_date = strtotime( $opts['max_date'] );*/
					$temp_date = date_create($opts['max_date'], new DateTimeZone( $tzone ) );
					if ( $temp_date ) {
						//$opts['max_date'] = date( $clean_format, $temp_date );
						$opts['max_date'] = $temp_date->format($clean_format);
						//$opts['max_year'] = date( 'Y', $temp_date );
						$opts['max_year'] = $temp_date->format('Y');
					}
				}

				// min date.
				if ( isset( $opts['min_date'] ) && $opts['min_date'] !== '' ) {
					/*2021.01 Edit set $tzone
					$temp_date = strtotime( $opts['min_date'] );*/
					$temp_date = date_create($opts['min_date'], new DateTimeZone( $tzone ) );
					
					if ( $temp_date ) {
						//$opts['min_date'] = date( $clean_format, $temp_date );
						$opts['min_date'] = $temp_date->format($clean_format);
						//$opts['min_year'] = date( 'Y', $temp_date );
						$opts['min_year'] = $temp_date->format('Y');
					} else {
						$opts['min_date'] = false;
					}
				}
			}