minor #6070 Update UPGRADE-v3.md with php_unit_test_annotation/case deprecation (kubawerlos)

This PR was merged into the master branch.

Discussion
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Update UPGRADE-v3.md with php_unit_test_annotation/case deprecation

Deprecation was added [here](https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/3886/files#diff-7b3ed02bc73dc06b7db906cf97aa91dec2b2eb21f2d92bc5caa761df5bbc168fR1330).

Commits
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195d1b315 Update UPGRADE-v3.md with php_unit_test_annotation/case deprecation

UPGRADE-v3.md

@@ -91,6 +91,7 @@ Rule | Option | Change
 `ordered_imports`                        | `importsOrder`                               | option was renamed, use `imports_order`
 `ordered_imports`                        | `sortAlgorithm`                              | option was renamed, use `sort_algorithm`
 `php_unit_dedicate_assert`               | `functions`                                  | option was removed, use `target` instead
+`php_unit_test_annotation`               | `case`                                       | option was removed, use `php_unit_method_casing` rule instead
 
 ### Changed default values of options