[#1550] Convert Timestamp to LocalDateTime for Db2

Instead of the default OffsetDateTime

Author: DavideD

hibernate-reactive-core/src/main/java/org/hibernate/reactive/provider/impl/ReactiveTypeContributor.java

@@ -18,6 +18,7 @@
 
 import org.hibernate.boot.model.TypeContributions;
 import org.hibernate.boot.model.TypeContributor;
+import org.hibernate.dialect.DB2Dialect;
 import org.hibernate.dialect.Dialect;
 import org.hibernate.dialect.MySQLDialect;
 import org.hibernate.dialect.PostgreSQLDialect;
@@ -76,7 +77,7 @@ private void registerReactiveChanges(TypeContributions typeContributions, Servic
 		JavaTypeRegistry javaTypeRegistry = typeConfiguration.getJavaTypeRegistry();
 		javaTypeRegistry.addDescriptor( JsonObjectJavaType.INSTANCE );
 
-		if ( dialect instanceof MySQLDialect ) {
+		if ( dialect instanceof MySQLDialect || dialect instanceof DB2Dialect ) {
 			JdbcTypeRegistry jdbcTypeRegistry = typeConfiguration.getJdbcTypeRegistry();
 			jdbcTypeRegistry.addDescriptor( TimestampAsLocalDateTimeJdbcType.INSTANCE );
 			jdbcTypeRegistry.addDescriptor( TimestampUtcAsLocalDateTimeJdbcType.INSTANCE );