minor symfony#27899 add @xabbuh as a code owner of the Yaml component (xabbuh)

This PR was merged into the 2.8 branch.

Discussion
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add @xabbuh as a code owner of the Yaml component

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Commits
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748cad4 add @xabbuh as a code owner of the Yaml component

Author: xabbuh

.github/CODEOWNERS

@@ -25,3 +25,5 @@
 /src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/ValidateWorkflowsPass.php @lyrixx
 /src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/WorkflowGuardListenerPass.php @lyrixx
 /src/Symfony/Component/Workflow/* @lyrixx
+# Yaml
+/src/Symfony/Component/Yaml/* @xabbuh