Bump the README

Update test matrix, bump minimium requirements (#19)

Vermeide Deprecation (Case 193321) (#17)

...durch Nutzung von
`Symfony\Component\DependencyInjection\Extension\Extension` an Stelle
von `Symfony\Component\HttpKernel\DependencyInjection\Extension`.

Read attributes as provided by the event object, and pass on attribut…

…es to other event handlers (Case 177753) (#15)

This adapts
webfactory/WebfactoryWfdMetaBundle#53:

> This PR uses the new API introduced in
symfony/symfony#46001 to read controller
attributes through the `ControllerEvent`, and to make them available to
other event handlers when replacing the controller.
>
> This is necessary when using the `Send304IfNotModified` attribute in
combination with `\Symfony\Component\HttpKernel\Attribute\Cache`.
Without this change,
`\Symfony\Component\HttpKernel\EventListener\CacheAttributeListener`
will not set `Cache` headers accordingly. The result is that you may get
`304 Not Modified` responses on conditional requests with
`If-Modified-Since`, but these are treated as `stale/cache` only in the
HttpCache and have a `Cache-Control: must-revalidate, private` header.

And adds some tests.

Remove annotations support to gain Symfony 7 compatibility (#11)

This removes the annotation that has been deprecated in 1.4.0. Thus, we get rid of the `doctrine/annotations` dependency and the `annotation_reader` service, clearing the path towards Symfony 7 compatibility.

The PHP 8.1 minimum requirement effectively limits usage with Symfony < 5.

Add a PHP 8 attribute for configuration (#10)

This adds a PHP 8 attribute for configuration, and deprecates using the old annotation class.

Allow Symfony 6 components (#8)

Modernize code and test setup, prepare for Symfony 5.x and PHP 8.x (#4)

Merge pull request #2 from webfactory/no-304-in-debug

Avoid sending 304s in Symfony kernel.debug mode

Ergänze Service-Id für Symfony 4-Kompatibilität (Case 107508)