Add support for Symfony 7 (#55)

* Add support for Symfony 7

* Upgrade PHPUnit

* Run annotation registry only when available

* Add return types to PHPUnit setup

* Add missing prophecy trait

* Remove PHPUnit 11 support

* Reformat phpunit.xml.dist file

Add symfony 6 comptability (#54)

* Add symfony 6 comptability

* Fix doctrine storage

* Fix unit test

* Update php-task version

Dispatch before / after events in ExecuteCommand (#53)

* Dispatch before / after events

* Add dispatcher bridge

Add PHP 8 support (#52)

* Add PHP 8 support

* Upgrade phpunit tests

* Fix PHP 8 compatibility

* Remove minimum stability for test lowest dependencies

Update branch alias

updated symfony components (#47)

updated packagist type

Added error-output as message for seperate-process exception (#45)

* added error-output as message for seperate-process exception

* fixed code-style

fixed version of php-task

removed hhvm from travis config