Update dependency org.hibernate:hibernate-core to v5.6.8.Final (#1641)

Co-authored-by: Renovate Bot <[email protected]>

Author: renovate[bot]

gradle.properties

@@ -10,7 +10,7 @@ jtaVersion=1.1
 javaAnnotationApiVersion=1.3.2
 elVersion=3.0.0
 commonsValidatorVersion=1.7
-hibernateVersion=5.6.7.Final
+hibernateVersion=5.6.8.Final
 servletApiVersion=4.0.1
 spockVersion=2.1-groovy-3.0
 springVersion=5.3.17