bug #44110 [FrameworkBundle] Fix default PHP attributes support in validation and serializer configuration when doctrine/annotations is not installed with PHP 8 (fancyweb)

This PR was merged into the 5.3 branch.

Discussion
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[FrameworkBundle] Fix default PHP attributes support in validation and serializer configuration when doctrine/annotations is not installed with PHP 8

| Q             | A
| ------------- | ---
| Branch?       | 5.3
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Afrer upgrading to PHP 8 and using real PHP attributes, I noticed there were no validation metadata for my classes anymore.

Before:
- Full default FWB validator config
- PHP 7.4
- Constraints in my code are declared as PHPDoc annotation (the old way)
- doctrine/annotations is required in composer.json

After:
- Full default FWB validator config
- PHP 8.0
- Constraints in my code are declared as real PHP attributes
- doctrine/annotations has been removed from composer.json because I don't need it anymore

I expect the migration to be transparent, ie not having to do any change in the config to switch from PHPDoc annotations to real PHP attributes. However, `validation.enable_annotations` does not default to true anymore after the migration so here is the fix. WDYT?

Commits
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c9be9704f0 [FrameworkBundle] Fix default PHP attributes support in validation and serializer configuration when doctrine/annotations is not installed with PHP 8

Author: fabpot

DependencyInjection/Configuration.php

@@ -859,7 +859,7 @@ private function addValidationSection(ArrayNodeDefinition $rootNode, callable $e
                     ->{$enableIfStandalone('symfony/validator', Validation::class)}()
                     ->children()
                         ->scalarNode('cache')->end()
-                        ->booleanNode('enable_annotations')->{!class_exists(FullStack::class) && $willBeAvailable('doctrine/annotations', Annotation::class, 'symfony/validator') ? 'defaultTrue' : 'defaultFalse'}()->end()
+                        ->booleanNode('enable_annotations')->{!class_exists(FullStack::class) && (\PHP_VERSION_ID >= 80000 || $willBeAvailable('doctrine/annotations', Annotation::class, 'symfony/validator')) ? 'defaultTrue' : 'defaultFalse'}()->end()
                         ->arrayNode('static_method')
                             ->defaultValue(['loadValidatorMetadata'])
                             ->prototype('scalar')->end()
@@ -942,8 +942,8 @@ private function addValidationSection(ArrayNodeDefinition $rootNode, callable $e
 
     private function addAnnotationsSection(ArrayNodeDefinition $rootNode, callable $willBeAvailable)
     {
-        $doctrineCache = $willBeAvailable('doctrine/cache', Cache::class, 'doctrine/annotation');
-        $psr6Cache = $willBeAvailable('symfony/cache', PsrCachedReader::class, 'doctrine/annotation');
+        $doctrineCache = $willBeAvailable('doctrine/cache', Cache::class, 'doctrine/annotations');
+        $psr6Cache = $willBeAvailable('symfony/cache', PsrCachedReader::class, 'doctrine/annotations');
 
         $rootNode
             ->children()
@@ -968,7 +968,7 @@ private function addSerializerSection(ArrayNodeDefinition $rootNode, callable $e
                     ->info('serializer configuration')
                     ->{$enableIfStandalone('symfony/serializer', Serializer::class)}()
                     ->children()
-                        ->booleanNode('enable_annotations')->{!class_exists(FullStack::class) && $willBeAvailable('doctrine/annotations', Annotation::class, 'symfony/serializer') ? 'defaultTrue' : 'defaultFalse'}()->end()
+                        ->booleanNode('enable_annotations')->{!class_exists(FullStack::class) && (\PHP_VERSION_ID >= 80000 || $willBeAvailable('doctrine/annotations', Annotation::class, 'symfony/serializer')) ? 'defaultTrue' : 'defaultFalse'}()->end()
                         ->scalarNode('name_converter')->end()
                         ->scalarNode('circular_reference_handler')->end()
                         ->scalarNode('max_depth_handler')->end()