minor symfony#54316 Add missing changelog for PR53898 (AurelienPillevesse)

This PR was merged into the 7.1 branch.

Discussion
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Add missing changelog for PR53898

| Q             | A
| ------------- | ---
| Branch?       | 7.1
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Issues        | -
| License       | MIT

Add missing changelog in my PR merged today : symfony#53898

Commits
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c86f689 add missing changelog for PR 53898

Author: fabpot

src/Symfony/Component/Serializer/CHANGELOG.md

@@ -7,6 +7,7 @@ CHANGELOG
  * Add `DateTimeNormalizer::CAST_KEY` context option
  * Add `Default` and "class name" default groups
  * Add `AbstractNormalizer::FILTER_BOOL` context option
+ * Add `CamelCaseToSnakeCaseNameConverter::REQUIRE_SNAKE_CASE_PROPERTIES` context option
 
 7.0
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