build(pom.xml): update hibernate-validator to 6.0.18.Final

Changelogs:
- https://in.relation.to/2019/06/13/hibernate-validator-6017-final-out/
- https://in.relation.to/2019/11/20/hibernate-validator-610-6018-released/

Author: php-coder

pom.xml

@@ -487,7 +487,7 @@
 		<h2.version>1.4.199</h2.version>
 
 		<!-- Redefine default value from spring-boot-dependencies -->
-		<hibernate-validator.version>6.0.16.Final</hibernate-validator.version>
+		<hibernate-validator.version>6.0.18.Final</hibernate-validator.version>
 
 		<!-- Redefine default value from spring-boot-dependencies -->
 		<hikaricp.version>3.4.1</hikaricp.version>