Upgrade Hibernate Validator to 6.0.9.Final

No migration concerns from 6.0.7.Final to 6.0.9.Final.

The important point is that a regression from 5.x to 6.0.x was fixed in this release: https://hibernate.atlassian.net/browse/HV-1596 .

We also reduced the memory allocation rate in some common use cases.

Full changelog of 6.0.8.Final:
https://hibernate.atlassian.net/projects/HV/versions/31620/tab/release-report-all-issues

Full changelog of 6.0.9.Final:
https://hibernate.atlassian.net/projects/HV/versions/31646/tab/release-report-all-issues