Bugfix release: fixed controller service in routing

• Support for Symfony 7, minimum required Symfony version is now 5.4.
• JMS\SerializerBundle is no longer a required dependency, symfony/serializer can be used instead.
• Configuration changes:
  • Use serialization_context instead of jms_serialization_context.
  • Use enable_max_depth' instead of max_depth_checks`.

Updated for Symfony 5 and 6 and PHP 8. Still needs more testing before using in production.

• Installation with Flex on symfony 4.x now works
• Fixed failing travis builds for PHP 5, removing tests for PHP 5.4 (minimal tested PHP Version is now 5.6)

• compatibility with Symfony 4, thanks to @shreypuranik
• make unit tests compatible with newer phpunit versions

Added compatibility with Symfony 3. Minimum required Symfony version is now 2.7

Function definitions can be added after instanciation of the service via JsonRpcController::addMethod()

use array instead of a StdClass object for decoded json request