feature #43898 [Security] Make the abstract Voter class implement CacheableVoterInterface (javiereguiluz)

This PR was squashed before being merged into the 5.4 branch.

Discussion
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[Security] Make the abstract Voter class implement CacheableVoterInterface

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Related to this --> https://symfony.com/blog/new-in-symfony-5-4-faster-security-voters

The abstract `Voter` class is "a helper" to simplify the creation of custom voters. I propose to implement the new `CacheableVoterInterface`, so this nice feature is easier to discover and ready-to-use for those developers extending `Voter`.

Commits
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f230d0f002 [Security] Make the abstract Voter class implement CacheableVoterInterface

Author: fabpot

Authorization/Voter/Voter.php

@@ -19,7 +19,7 @@
  * @author Roman Marintšenko <inoryy@gmail.com>
  * @author Grégoire Pineau <lyrixx@lyrixx.info>
  */
-abstract class Voter implements VoterInterface
+abstract class Voter implements VoterInterface, CacheableVoterInterface
 {
     /**
      * {@inheritdoc}
@@ -59,6 +59,26 @@ public function vote(TokenInterface $token, $subject, array $attributes)
         return $vote;
     }
 
+    /**
+     * Return false if your voter doesn't support the given attribute. Symfony will cache
+     * that decision and won't call your voter again for that attribute.
+     */
+    public function supportsAttribute(string $attribute): bool
+    {
+        return true;
+    }
+
+    /**
+     * Return false if your voter doesn't support the given subject type. Symfony will cache
+     * that decision and won't call your voter again for that subject type.
+     *
+     * @param string $subjectType The type of the subject inferred by `get_class()` or `get_debug_type()`
+     */
+    public function supportsType(string $subjectType): bool
+    {
+        return true;
+    }
+
     /**
      * Determines if the attribute and subject are supported by this voter.
      *