…ps opt (dunglas)This PR was merged into the 4.2-dev branch.Discussion----------[Serializer] Allow to pass a single value for the groups opt| Q             | A| ------------- | ---| Branch?       | master| Bug fix?      | no| New feature?  | yes <!-- don't forget to update src/**/CHANGELOG.md files -->| BC breaks?    | no     <!-- seehttps://symfony.com/bc -->| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->| Fixed tickets |  n/a| License       | MIT| Doc PR        | todoShortcut syntax similar to#20509 but for the context: allows to pass a string instead of an array of string in the serialization context when only one group if used.Before:```php$serializer->serialize($foo, 'json', ['groups' => ['myGroup']];/** @ApiResource(normalizationContext={"groups"={"myGroup"}}) */```After:```php$serializer->serialize($foo, 'json', ['groups' => 'myGroup'];/** @ApiResource(normalizationContext={"groups"="myGroup") */```Commits-------5b39203 [Serializer] Allow to pass a single value for the groups opt

… opt (dunglas, javiereguiluz)This PR was merged into the master branch.Discussion----------[Serializer] Allow to pass a single value for the groups optsymfony/symfony#27503Commits-------ae558f4 Added the missing versionadded directivee4eae25 Replaced a "note" by a "tip"5e0a91e [Serializer] Allow to pass a single value for the groups opt