Fix broken test that still used util.date instead of Java 8 datetime

src/test/java/org/eclipsefoundation/react/test/helper/DtoHelper.java

 package org.eclipsefoundation.react.test.helper;
 
-import java.time.Instant;
+import java.time.OffsetDateTime;
 import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.List;
 import java.util.Optional;
 import java.util.Random;
@@ -108,8 +107,7 @@ public class DtoHelper {
         wg.setWorkingGroupID(RandomStringUtils.randomAlphabetic(4, 10));
         wg.setParticipationLevel(RandomStringUtils.randomAlphabetic(4, 10));
         // get a random instance of time
-        Instant inst = Instant.now().minus(r.nextInt(1000000), ChronoUnit.SECONDS);
-        wg.setEffectiveDate(new Date(inst.getEpochSecond()));
+        wg.setEffectiveDate(OffsetDateTime.now().minus(r.nextInt(1000000), ChronoUnit.SECONDS));
         wg.setContact(generateContact(form, Optional.empty()));
         wg.setForm(form);
         return wg;