set seconds and milliseconds to zero

src/main/java/de/jottyfan/timetrack/modules/done/TimeService.java

@@ -30,7 +30,7 @@ public class TimeService {
 			} else {
 				offset = interval - compareMinute;
 			}
-			return givenTime.plusMinutes(offset);
+			return givenTime.plusMinutes(offset).withSecond(0).withNano(0);
 		}
 	}
 }