Add deprecation for method signature

Author: jderusse

CHANGELOG.md

@@ -21,6 +21,7 @@ CHANGELOG
  * added a new `notInRangeMessage` option to the `Range` constraint that will
    be used in the violation builder when both `min` and `max` are not null
  * added ability to use stringable objects as violation messages
+ * Overriding the methods `ConstraintValidatorTestCase::setUp()` and `ConstraintValidatorTestCase::tearDown()` without the `void` return-type is deprecated.
 
 4.3.0
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