minor symfony#57864 [Cache] document igbinary changes in the Cache component (xabbuh)

This PR was merged into the 7.2 branch.

Discussion
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[Cache] document igbinary changes in the Cache component

| Q             | A
| ------------- | ---
| Branch?       | 7.2
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        |
| License       | MIT

Commits
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a0bdc0f document igbinary changes in the Cache component

Author: xabbuh

UPGRADE-7.2.md

@@ -8,6 +8,11 @@ Read more about this in the [Symfony documentation](https://symfony.com/doc/7.2/
 
 If you're upgrading from a version below 7.1, follow the [7.1 upgrade guide](UPGRADE-7.1.md) first.
 
+Cache
+-----
+
+ * `igbinary_serialize()` is not used by default when the igbinary extension is installed
+
 Form
 ----
 

src/Symfony/Component/Cache/CHANGELOG.md

@@ -4,6 +4,7 @@ CHANGELOG
 7.2
 ---
 
+ * `igbinary_serialize()` is not used by default when the igbinary extension is installed
  * Add optional `Psr\Clock\ClockInterface` parameter to `ArrayAdapter`
 
 7.1