http_build_query: fix deprecated issues

[macbre]

E_DEPRECATED: http_build_query(): Passing null to parameter #2 ($numeric_prefix) of type string is deprecated

https://github.com/elecena/amazon-s3-php-class/blob/master/S3.php#L2015:

		$queryString = http_build_query($parameters, null, '&', PHP_QUERY_RFC3986);

https://www.php.net/http_build_query

[macbre]

$ composer run test
> phpunit -vvv --testdox
PHPUnit 9.5.25 #StandWithUkraine

Runtime:       PHP 8.1.10
Configuration: /Users/macbre/git/amazon-s3-php-class/phpunit.xml

S3Base
 ✔ Class is present in autoloader  2 ms

S3Guzzle
 ✔ Public file exists on s 3  206 ms
 ✔ Private file is not accessible  156 ms
 ✔ Class is present in autoloader  1 ms
PHP Deprecated:  http_build_query(): Passing null to parameter #2 ($numeric_prefix) of type string is deprecated in /Users/macbre/git/amazon-s3-php-class/S3.php on line 2015

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