2.0.2: 8-Force batch consumer to stop (#9)

• removing deprecated Debug package
• fixing BatchConsumer does not acknowledge gracefulExecutionTime

fixing setup:fabric in symfony 5

Allow symfony 5 fixes (#5)

fixing setup-fabric compatibility with sf5

Symfony 5 compatible

Changes were made to the library in order to make it compatible to Symfony 5, the minimum version required for it to run being 4.3

fixing compatibility with php 5.3

• add php7.3 in travis checking

• make code compatible with php 5.3

the builds are failing on php5.3 due the fact that php 5.3 doesn't support ::class constant.
The issue was introduced by: https://github.com/php-amqplib/RabbitMqBundle/pull/571/files

fixing deprecation notices caused in symfony 4.3

fixing deprecation notices caused by symfony 4.3.