Bump php-amqplib/php-amqplib from 2.12.3 to 3.0.0 in /legacy (#1418)

* Bump php-amqplib/php-amqplib from 2.12.3 to 3.0.0 in /legacy

Bumps [php-amqplib/php-amqplib](https://github.com/php-amqplib/php-amqplib) from 2.12.3 to 3.0.0.
- [Release notes](https://github.com/php-amqplib/php-amqplib/releases)
- [Changelog](https://github.com/php-amqplib/php-amqplib/blob/master/CHANGELOG.md)
- [Commits](https://github.com/php-amqplib/php-amqplib/compare/v2.12.3...v3.0.0)

---
updated-dependencies:
- dependency-name: php-amqplib/php-amqplib
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

* Replace deprecated AMQPConnection with AMQPStreamConnection

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: jo <ljonas@riseup.net>

legacy/public/setup/rabbitmq-setup.php

@@ -61,7 +61,7 @@ class RabbitMQSetup extends Setup
 
     public function checkRMQConnection()
     {
-        $conn = new \PhpAmqpLib\Connection\AMQPConnection(
+        $conn = new \PhpAmqpLib\Connection\AMQPStreamConnection(
             self::$_properties['host'],
             self::$_properties['port'],
             self::$_properties['user'],