Support Symfony 6.0

[dunglas]

Now that we support Symfony 5.4, we must also support Symfony 6.0.

• Checkout the 2.6 branch
• Add allow the ^6.0 version for all Symfony projects
• Run the test suite
• Remove the annoying type hints from Symfony's interfaces (open PR and ping me)

[leeroynico]

I work on it

[Chris53897]

This ticket is not so easy. I will try to help with this.
I think 2 steps are necessary in my point of view.

1. Build a Pipeline and allow symfony 6 in dependencies to get an overview of how much work is needed to support symfony 6.
2. Decide if APIP 2.x needs support for Symfony 6. Or only APIP 3.x with PHP8. Because you can not make a project compatible with Symfony 6 if you do not require Php >8. At least i do not know a way to do this.

To 1)

The CI Pipeline will not test all symfony 6 packages. Symfony 6.0 needs to be added to the test-matrix on 2 places (this allows the 2 additional packages to be tested against 6.0. Example Test-Run

Some symfony components are sticked to 5.4 because of dependencies.
(The link mink-repo is merged now, but the tests are not covering symfony 6.)

Example:
composer why symfony/browser-kit
...
friends-of-behat/mink-browserkit-driver v1.5.0 requires symfony/browser-kit (^4.4|^5.0)

I made a PR draft
and will try to update b) PR.
a) Origin https://github.com/minkphp/driver-testsuite (is still supporting Php > 5.6)
b) Fork of a) https://github.com/FriendsOfBehat/driver-testsuite (is used in friends-of-behat/mink-browserkit-driver)

[Chris53897]

update:
One blocker is gone.
Here i wait for a new release.
minkphp/Mink#814

After that "soyuka/contexts" could be updated too.

Now that 6.x is stable the CI Tests should be easier.