Bump hibernate-validator from 6.1.2.Final to 6.1.5.Final in /java

Bumps [hibernate-validator](https://github.com/hibernate/hibernate-validator) from 6.1.2.Final to 6.1.5.Final.
- [Release notes](https://github.com/hibernate/hibernate-validator/releases)
- [Changelog](https://github.com/hibernate/hibernate-validator/blob/6.1.5.Final/changelog.txt)
- [Commits](hibernate/hibernate-validator@6.1.2.Final...6.1.5.Final)

---
updated-dependencies:
- dependency-name: org.hibernate.validator:hibernate-validator
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

java/pom.xml

@@ -79,7 +79,7 @@
         <javax.validation.version>2.0.1.Final</javax.validation.version>
         <springfox.version>2.8.0</springfox.version>
         <google.auth.library.oauth2.http.version>0.20.0</google.auth.library.oauth2.http.version>
-        <org.hibernate.validator.version>6.1.2.Final</org.hibernate.validator.version>
+        <org.hibernate.validator.version>6.1.5.Final</org.hibernate.validator.version>
         <auto.value.version>1.6.6</auto.value.version>
 
         <license.content><![CDATA[