Upgrade Hibernate Validator to 6.0.16.Final

Hibernate Validator 6.0.x is faster than Hibernate Validator 5.x when validating constrained beans.

However, it has been reported to us that Hibernate Validator 6.0.x was significantly slower than Hibernate Validator 5.x when validating unconstrained beans due to a higher memory allocation rate.

This issue has been fixed in Hibernate Validator 6.0.16.Final, together with a rounding error issue.

We now also have a JMH benchmark for this particular use case.

The full changelog is here: https://hibernate.atlassian.net/issues/?jql=project%20%3D%20HV%20AND%20fixVersion%20%3D%206.0.16.Final%20order%20by%20created%20DESC .