Replaced unsupported Medium attribute on methods with Group('slow')

[maryo]

#[Medium] attribute can target only classes, #[Group('medium')] also cannot be applied.
Group name "medium" is not allowed for method tests\integration\Cache\Psr6CacheTest::testExpiration
Therefore i used #[Group('slow')], or it can be dropped entirely, or a different name.

[Nyholm]

Oh no.. I merged #119. I did not see this. Im sorry.

Is there anything left to do if you rebase on master?

[maryo]

Yes, rebased, there is still the issue with Medium attribute.

An error occurred inside PHPUnit.

Message:  Attribute "PHPUnit\Framework\Attributes\Medium" cannot target method (allowed targets: class)

@medium will be implemented as PHPUnit\Framework\Attributes\Medium (only allowed on classes; @medium was allowed on methods but it does not make sense to mix tests of different sizes in a test case class)
sebastianbergmann/phpunit#4502

I replaced it with Group('slow') (there is sleep(3)), or it can be dropped entirely, or do you prefer a different group name?

[Nyholm]

Thank you. I think it looks alright.

@xabbuh can you please review this?

[xabbuh]

👍 works for me

[Nyholm]

Thank you