PHP Strict standards => arguments list for get_filename() method

# Error (wp-cli)
PHP Strict standards:  Declaration of CLI_Migrate::get_filename() should be compatible with WP_Migrate_DB::get_filename($datetime, $gzip) in /var/www/wordpress/web/app/plugins/WP-CLI-Migrate-master/lib/migrate.php on line 166

# Resolution
Corrected arguments list passed to method get_filename() in WP-CLI-Migrate-master/lib/migrate.php