Upgrade to Hibernate Validator 6.0.15.Final

Closes gh-16124

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -70,7 +70,7 @@
 		<hazelcast-hibernate5.version>1.2.3</hazelcast-hibernate5.version>
 		<hibernate.version>5.2.18.Final</hibernate.version>
 		<hibernate-jpa-2.1-api.version>1.0.2.Final</hibernate-jpa-2.1-api.version>
-		<hibernate-validator.version>6.0.14.Final</hibernate-validator.version>
+		<hibernate-validator.version>6.0.15.Final</hibernate-validator.version>
 		<hikaricp.version>2.7.9</hikaricp.version>
 		<hsqldb.version>2.4.1</hsqldb.version>
 		<htmlunit.version>2.29</htmlunit.version>