Submit multiply locations

How to change the select location dropdown to multiply select?

// /wp-job-manager-locations/includes/class-template.php

public function submit_job_form_fields( $fields ) {
		$fields[ 'job' ][ 'job_region' ] = array(
			'label'       => __( 'Job Region', 'wp-job-manager-locations' ),
			'type'        => 'term-select',
			'taxonomy'    => 'job_listing_region',
			'required'    => true,
			'priority'    => '2.5',
			'default'     => -1
		);

		return $fields;
	}