Support Symfony 8 and bump doctrine dependencies

[acrobat]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	yes
Related tickets
License	MIT

PR to prepare this package for newer symfony and doctrine versions and to unblock other dependencies down the road (sylius/resource-bundle for example)

• Allow Symfony 8 and remove support for unmaintained Symfony 7 versions
• Bump doctrine/data-fixtures to v2 to allow doctrine/persitence v4
  • With this bump doctrine/doctrine-bundle v3 can also be allowed which will unblock Symfony 8 when v3.1 is released

Dependencies with pending Symfony 8 support:

Dependency	Info
doctrine/doctrine-bundle	symfony 8 support available in 3.1.x-dev
doctrine/orm	symfony 8 support available in 3.6.x-dev
nelmio/alice	https://github.com/nelmio/alice/pull/1284
theofidry/alice-data-fixtures	Not compatible yet (no work started) https://github.com/theofidry/AliceDataFixtures/issues/318

[lchrusciel]

Do you consider fixing build or should I take it over?

[acrobat]

Yeah sure, I will take a look at the tests! Most of them are passing now but some downstream dependencies still need a update for Symfony 8. I will first fix them and ping you when this PR is ready!

[acrobat]

@lchrusciel so far this PR is ready but to make the tests pass we're still waiting for upstream releases of dependencies. I've listed these dependencies in the PR description